wip-9189: including client metadata when opening sessions by jcsp · Pull Request #6 · ceph/ceph-client

jcsp · 2014-09-15T13:00:03Z

No description provided.

Implement version 2 of CEPH_MSG_CLIENT_SESSION syntax, which includes additional client metadata to allow the MDS to report on clients by user-sensible names like hostname. Signed-off-by: John Spray <john.spray@redhat.com>

ukernel · 2014-09-18T02:33:39Z

I updated the commit (using ceph_encode_xxx) and pushed it to testing branch

If the inode is same and its data index are needed to truncate, we can fall into double lock for its inode page via get_dnode_of_data. Error case is like this. 1. write data 1, 2, 3, 4, 5 in inode #4. 2. write data 100, 102, 103, 104, 105 in dnode #6 of inode #4. 3. sync 4. update data 100->106 in dnode #6. 5. fsync inode #4. 6. power-cut -> Then, 1. go back to #3's checkpoint 2. in do_recover_data, get_dnode_of_data() gets inode #4. 3. detect 100->106 in dnode #6. 4. check_index_in_prev_nodes tries to truncate 100 in dnode #6. 5. to trigger truncate_hole, get_dnode_of_data should grab inode #4. 6. detect *kernel hang* This patch should resolve that bug. Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

I'm getting the spew below when booting with Haswell (Xeon E5-2699 v3) CPUs and the "Cluster-on-Die" (CoD) feature enabled in the BIOS. It seems similar to the issue that some folks from AMD ran in to on their systems and addressed in this commit: 161270f ("x86/smp: Fix topology checks on AMD MCM CPUs") Both these Intel and AMD systems break an assumption which is being enforced by topology_sane(): a socket may not contain more than one NUMA node. AMD special-cased their system by looking for a cpuid flag. The Intel mode is dependent on BIOS options and I do not know of a way which it is enumerated other than the tables being parsed during the CPU bringup process. In other words, we have to trust the ACPI tables <shudder>. This detects the situation where a NUMA node occurs at a place in the middle of the "CPU" sched domains. It replaces the default topology with one that relies on the NUMA information from the firmware (SRAT table) for all levels of sched domains above the hyperthreads. This also fixes a sysfs bug. We used to freak out when we saw the "mc" group cross a node boundary, so we stopped building the MC group. MC gets exported as the 'core_siblings_list' in /sys/devices/system/cpu/cpu*/topology/ and this caused CPUs with the same 'physical_package_id' to not be listed together in 'core_siblings_list'. This violates a statement from Documentation/ABI/testing/sysfs-devices-system-cpu: core_siblings: internal kernel map of cpu#'s hardware threads within the same physical_package_id. core_siblings_list: human-readable list of the logical CPU numbers within the same physical_package_id as cpu#. The sysfs effects here cause an issue with the hwloc tool where it gets confused and thinks there are more sockets than are physically present. Before this patch, there are two packages: # cd /sys/devices/system/cpu/ # cat cpu*/topology/physical_package_id | sort | uniq -c 18 0 18 1 But 4 _sets_ of core siblings: # cat cpu*/topology/core_siblings_list | sort | uniq -c 9 0-8 9 18-26 9 27-35 9 9-17 After this set, there are only 2 sets of core siblings, which is what we expect for a 2-socket system. # cat cpu*/topology/physical_package_id | sort | uniq -c 18 0 18 1 # cat cpu*/topology/core_siblings_list | sort | uniq -c 18 0-17 18 18-35 Example spew: ... NMI watchdog: enabled on all CPUs, permanently consumes one hw-PMU counter. #2 #3 #4 #5 #6 #7 #8 .... node #1, CPUs: #9 ------------[ cut here ]------------ WARNING: CPU: 9 PID: 0 at /home/ak/hle/linux-hle-2.6/arch/x86/kernel/smpboot.c:306 topology_sane.isra.2+0x74/0x90() sched: CPU #9's mc-sibling CPU #0 is not on the same node! [node: 1 != 0]. Ignoring dependency. Modules linked in: CPU: 9 PID: 0 Comm: swapper/9 Not tainted 3.17.0-rc1-00293-g8e01c4d-dirty #631 Hardware name: Intel Corporation S2600WTT/S2600WTT, BIOS GRNDSDP1.86B.0036.R05.1407140519 07/14/2014 0000000000000009 ffff88046ddabe00 ffffffff8172e485 ffff88046ddabe48 ffff88046ddabe38 ffffffff8109691d 000000000000b001 0000000000000009 ffff88086fc12580 000000000000b020 0000000000000009 ffff88046ddabe98 Call Trace: [<ffffffff8172e485>] dump_stack+0x45/0x56 [<ffffffff8109691d>] warn_slowpath_common+0x7d/0xa0 [<ffffffff8109698c>] warn_slowpath_fmt+0x4c/0x50 [<ffffffff81074f94>] topology_sane.isra.2+0x74/0x90 [<ffffffff8107530e>] set_cpu_sibling_map+0x31e/0x4f0 [<ffffffff8107568d>] start_secondary+0x1ad/0x240 ---[ end trace 3fe5f587a9fcde61 ]--- #10 #11 #12 #13 #14 #15 #16 #17 .... node #2, CPUs: #18 #19 #20 #21 #22 #23 #24 #25 #26 .... node #3, CPUs: #27 #28 #29 #30 #31 #32 #33 #34 #35 Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> [ Added LLC domain and s/match_mc/match_die/ ] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Borislav Petkov <bp@alien8.de> Cc: David Rientjes <rientjes@google.com> Cc: Igor Mammedov <imammedo@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Toshi Kani <toshi.kani@hp.com> Cc: brice.goglin@gmail.com Cc: "H. Peter Anvin" <hpa@linux.intel.com> Link: http://lkml.kernel.org/r/20140918193334.C065EBCE@viggo.jf.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>

For commit ocfs2 journal, ocfs2 journal thread will acquire the mutex osb->journal->j_trans_barrier and wake up jbd2 commit thread, then it will wait until jbd2 commit thread done. In order journal mode, jbd2 needs flushing dirty data pages first, and this needs get page lock. So osb->journal->j_trans_barrier should be got before page lock. But ocfs2_write_zero_page() and ocfs2_write_begin_inline() obey this locking order, and this will cause deadlock and hung the whole cluster. One deadlock catched is the following: PID: 13449 TASK: ffff8802e2f08180 CPU: 31 COMMAND: "oracle" #0 [ffff8802ee3f79b0] __schedule at ffffffff8150a524 #1 [ffff8802ee3f7a58] schedule at ffffffff8150acbf #2 [ffff8802ee3f7a68] rwsem_down_failed_common at ffffffff8150cb85 #3 [ffff8802ee3f7ad8] rwsem_down_read_failed at ffffffff8150cc55 #4 [ffff8802ee3f7ae8] call_rwsem_down_read_failed at ffffffff812617a4 #5 [ffff8802ee3f7b50] ocfs2_start_trans at ffffffffa0498919 [ocfs2] #6 [ffff8802ee3f7ba0] ocfs2_zero_start_ordered_transaction at ffffffffa048b2b8 [ocfs2] #7 [ffff8802ee3f7bf0] ocfs2_write_zero_page at ffffffffa048e9bd [ocfs2] #8 [ffff8802ee3f7c80] ocfs2_zero_extend_range at ffffffffa048ec83 [ocfs2] #9 [ffff8802ee3f7ce0] ocfs2_zero_extend at ffffffffa048edfd [ocfs2] #10 [ffff8802ee3f7d50] ocfs2_extend_file at ffffffffa049079e [ocfs2] #11 [ffff8802ee3f7da0] ocfs2_setattr at ffffffffa04910ed [ocfs2] #12 [ffff8802ee3f7e70] notify_change at ffffffff81187d29 #13 [ffff8802ee3f7ee0] do_truncate at ffffffff8116bbc1 #14 [ffff8802ee3f7f50] sys_ftruncate at ffffffff8116bcbd #15 [ffff8802ee3f7f80] system_call_fastpath at ffffffff81515142 RIP: 00007f8de750c6f7 RSP: 00007fffe786e478 RFLAGS: 00000206 RAX: 000000000000004d RBX: ffffffff81515142 RCX: 0000000000000000 RDX: 0000000000000200 RSI: 0000000000028400 RDI: 000000000000000d RBP: 00007fffe786e040 R8: 0000000000000000 R9: 000000000000000d R10: 0000000000000000 R11: 0000000000000206 R12: 000000000000000d R13: 00007fffe786e710 R14: 00007f8de70f8340 R15: 0000000000028400 ORIG_RAX: 000000000000004d CS: 0033 SS: 002b crash64> bt PID: 7610 TASK: ffff88100fd56140 CPU: 1 COMMAND: "ocfs2cmt" #0 [ffff88100f4d1c50] __schedule at ffffffff8150a524 #1 [ffff88100f4d1cf8] schedule at ffffffff8150acbf #2 [ffff88100f4d1d08] jbd2_log_wait_commit at ffffffffa01274fd [jbd2] #3 [ffff88100f4d1d98] jbd2_journal_flush at ffffffffa01280b4 [jbd2] #4 [ffff88100f4d1dd8] ocfs2_commit_cache at ffffffffa0499b14 [ocfs2] #5 [ffff88100f4d1e38] ocfs2_commit_thread at ffffffffa0499d38 [ocfs2] #6 [ffff88100f4d1ee8] kthread at ffffffff81090db6 #7 [ffff88100f4d1f48] kernel_thread_helper at ffffffff81516284 crash64> bt PID: 7609 TASK: ffff88100f2d4480 CPU: 0 COMMAND: "jbd2/dm-20-86" #0 [ffff88100def3920] __schedule at ffffffff8150a524 #1 [ffff88100def39c8] schedule at ffffffff8150acbf #2 [ffff88100def39d8] io_schedule at ffffffff8150ad6c #3 [ffff88100def39f8] sleep_on_page at ffffffff8111069e #4 [ffff88100def3a08] __wait_on_bit_lock at ffffffff8150b30a #5 [ffff88100def3a58] __lock_page at ffffffff81110687 #6 [ffff88100def3ab8] write_cache_pages at ffffffff8111b752 #7 [ffff88100def3be8] generic_writepages at ffffffff8111b901 #8 [ffff88100def3c48] journal_submit_data_buffers at ffffffffa0120f67 [jbd2] #9 [ffff88100def3cf8] jbd2_journal_commit_transaction at ffffffffa0121372[jbd2] #10 [ffff88100def3e68] kjournald2 at ffffffffa0127a86 [jbd2] #11 [ffff88100def3ee8] kthread at ffffffff81090db6 #12 [ffff88100def3f48] kernel_thread_helper at ffffffff81516284 Signed-off-by: Junxiao Bi <junxiao.bi@oracle.com> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Alex Chen <alex.chen@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This patch wires up the new syscall sys_bpf() on powerpc. Passes the tests in samples/bpf: #0 add+sub+mul OK #1 unreachable OK #2 unreachable2 OK #3 out of range jump OK #4 out of range jump2 OK #5 test1 ld_imm64 OK #6 test2 ld_imm64 OK #7 test3 ld_imm64 OK #8 test4 ld_imm64 OK #9 test5 ld_imm64 OK #10 no bpf_exit OK #11 loop (back-edge) OK #12 loop2 (back-edge) OK #13 conditional loop OK #14 read uninitialized register OK #15 read invalid register OK #16 program doesn't init R0 before exit OK #17 stack out of bounds OK #18 invalid call insn1 OK #19 invalid call insn2 OK #20 invalid function call OK #21 uninitialized stack1 OK #22 uninitialized stack2 OK #23 check valid spill/fill OK #24 check corrupted spill/fill OK #25 invalid src register in STX OK #26 invalid dst register in STX OK #27 invalid dst register in ST OK #28 invalid src register in LDX OK #29 invalid dst register in LDX OK #30 junk insn OK #31 junk insn2 OK #32 junk insn3 OK #33 junk insn4 OK #34 junk insn5 OK #35 misaligned read from stack OK #36 invalid map_fd for function call OK #37 don't check return value before access OK #38 access memory with incorrect alignment OK #39 sometimes access memory with incorrect alignment OK #40 jump test 1 OK #41 jump test 2 OK #42 jump test 3 OK #43 jump test 4 OK Signed-off-by: Pranith Kumar <bobby.prani@gmail.com> [mpe: test using samples/bpf] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This reverts commit aa11bbf. This commit was causing connection issues and is not needed if IWL_MVM_RS_RSSI_BASED_INIT_RATE is set to false by default. Regardless of the issues mentioned above, this patch added the following WARNING: WARNING: CPU: 0 PID: 3946 at drivers/net/wireless/iwlwifi/mvm/tx.c:190 iwl_mvm_set_tx_params+0x60a/0x6f0 [iwlmvm]() Got an HT rate for a non data frame 0x8 CPU: 0 PID: 3946 Comm: wpa_supplicant Tainted: G O 3.17.0+ #6 Hardware name: LENOVO 20ANCTO1WW/20ANCTO1WW, BIOS GLET71WW (2.25 ) 07/02/2014 0000000000000009 ffffffff814fa911 ffff8804288db8f8 ffffffff81064f52 0000000000001808 ffff8804288db948 ffff88040add8660 ffff8804291b5600 0000000000000000 ffffffff81064fb7 ffffffffa07b73d0 0000000000000020 Call Trace: [<ffffffff814fa911>] ? dump_stack+0x41/0x51 [<ffffffff81064f52>] ? warn_slowpath_common+0x72/0x90 [<ffffffff81064fb7>] ? warn_slowpath_fmt+0x47/0x50 [<ffffffffa07a39ea>] ? iwl_mvm_set_tx_params+0x60a/0x6f0 [iwlmvm] [<ffffffffa07a3cf8>] ? iwl_mvm_tx_skb+0x48/0x3c0 [iwlmvm] [<ffffffffa079cb9b>] ? iwl_mvm_mac_tx+0x7b/0x180 [iwlmvm] [<ffffffffa0746ce9>] ? __ieee80211_tx+0x2b9/0x3c0 [mac80211] [<ffffffffa07492f3>] ? ieee80211_tx+0xb3/0x100 [mac80211] [<ffffffffa0749c49>] ? ieee80211_subif_start_xmit+0x459/0xca0 [mac80211] [<ffffffff814116e7>] ? dev_hard_start_xmit+0x337/0x5f0 [<ffffffff81430d46>] ? sch_direct_xmit+0x96/0x1f0 [<ffffffff81411ba3>] ? __dev_queue_xmit+0x203/0x4f0 [<ffffffff8142f670>] ? ether_setup+0x70/0x70 [<ffffffff814e96a1>] ? packet_sendmsg+0xf81/0x1110 [<ffffffff8140625c>] ? skb_free_datagram+0xc/0x40 [<ffffffff813f7538>] ? sock_sendmsg+0x88/0xc0 [<ffffffff813f7274>] ? move_addr_to_kernel.part.20+0x14/0x60 [<ffffffff811c47c2>] ? __inode_wait_for_writeback+0x62/0xb0 [<ffffffff813f7a91>] ? SYSC_sendto+0xf1/0x180 [<ffffffff813f88f9>] ? __sys_recvmsg+0x39/0x70 [<ffffffff8150066d>] ? system_call_fastpath+0x1a/0x1f ---[ end trace cc19a150d311fc63 ]--- which was reported here: https://bugzilla.kernel.org/show_bug.cgi?id=85691 CC: <stable@vger.kernel.org> [3.13+] Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

Firmware-assisted dump (fadump) kernel code is not endian safe. The below patch fixes this issue. Tested this patch with upstream kernel. Below output shows crash tool successfully opening LE fadump vmcore. # crash vmlinux vmcore GNU gdb (GDB) 7.6 This GDB was configured as "powerpc64le-unknown-linux-gnu"... KERNEL: vmlinux DUMPFILE: vmcore CPUS: 16 DATE: Wed Dec 31 19:00:00 1969 UPTIME: 00:03:28 LOAD AVERAGE: 0.46, 0.86, 0.41 TASKS: 268 NODENAME: linux-dhr2 RELEASE: 3.17.0-rc5-7-default VERSION: #6 SMP Tue Sep 30 01:06:34 EDT 2014 MACHINE: ppc64le (4116 Mhz) MEMORY: 40 GB PANIC: "Oops: Kernel access of bad area, sig: 11 [#1]" (check log for details) PID: 6223 COMMAND: "bash" TASK: c0000009661b2500 [THREAD_INFO: c000000967ac0000] CPU: 2 STATE: TASK_RUNNING (PANIC) Signed-off-by: Hari Bathini <hbathini@linux.vnet.ibm.com> [mpe: Make the comment in pSeries_lpar_hptab_clear() clearer] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

commit 1ffde69 upstream. This reverts commit aa11bbf. This commit was causing connection issues and is not needed if IWL_MVM_RS_RSSI_BASED_INIT_RATE is set to false by default. Regardless of the issues mentioned above, this patch added the following WARNING: WARNING: CPU: 0 PID: 3946 at drivers/net/wireless/iwlwifi/mvm/tx.c:190 iwl_mvm_set_tx_params+0x60a/0x6f0 [iwlmvm]() Got an HT rate for a non data frame 0x8 CPU: 0 PID: 3946 Comm: wpa_supplicant Tainted: G O 3.17.0+ #6 Hardware name: LENOVO 20ANCTO1WW/20ANCTO1WW, BIOS GLET71WW (2.25 ) 07/02/2014 0000000000000009 ffffffff814fa911 ffff8804288db8f8 ffffffff81064f52 0000000000001808 ffff8804288db948 ffff88040add8660 ffff8804291b5600 0000000000000000 ffffffff81064fb7 ffffffffa07b73d0 0000000000000020 Call Trace: [<ffffffff814fa911>] ? dump_stack+0x41/0x51 [<ffffffff81064f52>] ? warn_slowpath_common+0x72/0x90 [<ffffffff81064fb7>] ? warn_slowpath_fmt+0x47/0x50 [<ffffffffa07a39ea>] ? iwl_mvm_set_tx_params+0x60a/0x6f0 [iwlmvm] [<ffffffffa07a3cf8>] ? iwl_mvm_tx_skb+0x48/0x3c0 [iwlmvm] [<ffffffffa079cb9b>] ? iwl_mvm_mac_tx+0x7b/0x180 [iwlmvm] [<ffffffffa0746ce9>] ? __ieee80211_tx+0x2b9/0x3c0 [mac80211] [<ffffffffa07492f3>] ? ieee80211_tx+0xb3/0x100 [mac80211] [<ffffffffa0749c49>] ? ieee80211_subif_start_xmit+0x459/0xca0 [mac80211] [<ffffffff814116e7>] ? dev_hard_start_xmit+0x337/0x5f0 [<ffffffff81430d46>] ? sch_direct_xmit+0x96/0x1f0 [<ffffffff81411ba3>] ? __dev_queue_xmit+0x203/0x4f0 [<ffffffff8142f670>] ? ether_setup+0x70/0x70 [<ffffffff814e96a1>] ? packet_sendmsg+0xf81/0x1110 [<ffffffff8140625c>] ? skb_free_datagram+0xc/0x40 [<ffffffff813f7538>] ? sock_sendmsg+0x88/0xc0 [<ffffffff813f7274>] ? move_addr_to_kernel.part.20+0x14/0x60 [<ffffffff811c47c2>] ? __inode_wait_for_writeback+0x62/0xb0 [<ffffffff813f7a91>] ? SYSC_sendto+0xf1/0x180 [<ffffffff813f88f9>] ? __sys_recvmsg+0x39/0x70 [<ffffffff8150066d>] ? system_call_fastpath+0x1a/0x1f ---[ end trace cc19a150d311fc63 ]--- which was reported here: https://bugzilla.kernel.org/show_bug.cgi?id=85691 Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

David reported that perf can segfault when adding an uprobe event like this: $ perf probe -x /lib64/libc-2.14.90.so -a 'malloc size=%di' (gdb) bt #0 parse_eh_frame_hdr (hdr=0x0, hdr_size=2596, hdr_vaddr=71788, ehdr=0x7fffffffd390, eh_frame_vaddr= 0x7fffffffd378, table_entries=0x8808d8, table_encoding=0x8808e0 "") at dwarf_getcfi_elf.c:79 #1 0x000000385f81615a in getcfi_scn_eh_frame (hdr_vaddr=71788, hdr_scn=0x8839b0, shdr=0x7fffffffd2f0, scn=<optimized out>, ehdr=0x7fffffffd390, elf=0x882b30) at dwarf_getcfi_elf.c:231 #2 getcfi_shdr (ehdr=0x7fffffffd390, elf=0x882b30) at dwarf_getcfi_elf.c:283 #3 dwarf_getcfi_elf (elf=0x882b30) at dwarf_getcfi_elf.c:309 #4 0x00000000004d5bac in debuginfo__find_probes (pf=0x7fffffffd4f0, dbg=Unhandled dwarf expression opcode 0xfa) at util/probe-finder.c:993 #5 0x00000000004d634a in debuginfo__find_trace_events (dbg=0x880840, pev=<optimized out>, tevs=0x880f88, max_tevs=<optimized out>) at util/probe-finder.c:1200 #6 0x00000000004aed6b in try_to_find_probe_trace_events (target=0x881b20 "/lib64/libpthread-2.14.90.so", max_tevs=128, tevs=0x880f88, pev=0x859b30) at util/probe-event.c:482 #7 convert_to_probe_trace_events (target=0x881b20 "/lib64/libpthread-2.14.90.so", max_tevs=128, tevs=0x880f88, pev=0x859b30) at util/probe-event.c:2356 #8 add_perf_probe_events (pevs=<optimized out>, npevs=1, max_tevs=128, target=0x881b20 "/lib64/libpthread-2.14.90.so", force_add=false) at util/probe-event.c:2391 #9 0x000000000044014f in __cmd_probe (argc=<optimized out>, argv=0x7fffffffe2f0, prefix=Unhandled dwarf expression opcode 0xfa) at at builtin-probe.c:488 #10 0x0000000000440313 in cmd_probe (argc=5, argv=0x7fffffffe2f0, prefix=<optimized out>) at builtin-probe.c:506 #11 0x000000000041d133 in run_builtin (p=0x805680, argc=5, argv=0x7fffffffe2f0) at perf.c:341 #12 0x000000000041c8b2 in handle_internal_command (argv=<optimized out>, argc=<optimized out>) at perf.c:400 #13 run_argv (argv=<optimized out>, argcp=<optimized out>) at perf.c:444 #14 main (argc=5, argv=0x7fffffffe2f0) at perf.c:559 And I found a related commit (5704c8c4fa71 "getcfi_scn_eh_frame: Don't crash and burn when .eh_frame bits aren't there.") in elfutils that can lead to a unexpected crash like this. To safely use the function, it needs to check the .eh_frame section is a PROGBITS type. Reported-by: David Ahern <dsahern@gmail.com> Tested-by: David Ahern <dsahern@gmail.com> Signed-off-by: Namhyung Kim <namhyung@kernel.org> Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: David Ahern <dsahern@gmail.com> Cc: Mark Wielaard <mjw@redhat.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Link: http://lkml.kernel.org/r/20141230090533.GH6081@sejong Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

It is possible for ata_sff_flush_pio_task() to set ap->hsm_task_state to HSM_ST_IDLE in between the time __ata_sff_port_intr() checks for HSM_ST_IDLE and before it calls ata_sff_hsm_move() causing ata_sff_hsm_move() to BUG(). This problem is hard to reproduce making this patch hard to verify, but this fix will prevent the race. I have not been able to reproduce the problem, but here is a crash dump from a 2.6.32 kernel. On examining the ata port's state, its hsm_task_state field has a value of HSM_ST_IDLE: crash> struct ata_port.hsm_task_state ffff881c1121c000 hsm_task_state = 0 Normally, this should not be possible as ata_sff_hsm_move() was called from ata_sff_host_intr(), which checks hsm_task_state and won't call ata_sff_hsm_move() if it has a HSM_ST_IDLE value. PID: 11053 TASK: ffff8816e846cae0 CPU: 0 COMMAND: "sshd" #0 [ffff88008ba03960] machine_kexec at ffffffff81038f3b #1 [ffff88008ba039c0] crash_kexec at ffffffff810c5d92 #2 [ffff88008ba03a90] oops_end at ffffffff8152b510 #3 [ffff88008ba03ac0] die at ffffffff81010e0b #4 [ffff88008ba03af0] do_trap at ffffffff8152ad74 #5 [ffff88008ba03b50] do_invalid_op at ffffffff8100cf95 #6 [ffff88008ba03bf0] invalid_op at ffffffff8100bf9b [exception RIP: ata_sff_hsm_move+317] RIP: ffffffff813a77ad RSP: ffff88008ba03ca0 RFLAGS: 00010097 RAX: 0000000000000000 RBX: ffff881c1121dc60 RCX: 0000000000000000 RDX: ffff881c1121dd10 RSI: ffff881c1121dc60 RDI: ffff881c1121c000 RBP: ffff88008ba03d00 R8: 0000000000000000 R9: 000000000000002e R10: 000000000001003f R11: 000000000000009b R12: ffff881c1121c000 R13: 0000000000000000 R14: 0000000000000050 R15: ffff881c1121dd78 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 #7 [ffff88008ba03d08] ata_sff_host_intr at ffffffff813a7fbd #8 [ffff88008ba03d38] ata_sff_interrupt at ffffffff813a821e #9 [ffff88008ba03d78] handle_IRQ_event at ffffffff810e6ec0 --- <IRQ stack> --- [exception RIP: pipe_poll+48] RIP: ffffffff81192780 RSP: ffff880f26d459b8 RFLAGS: 00000246 RAX: 0000000000000000 RBX: ffff880f26d459c8 RCX: 0000000000000000 RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff881a0539fa80 RBP: ffffffff8100bb8e R8: ffff8803b23324a0 R9: 0000000000000000 R10: ffff880f26d45dd0 R11: 0000000000000008 R12: ffffffff8109b646 R13: ffff880f26d45948 R14: 0000000000000246 R15: 0000000000000246 ORIG_RAX: ffffffffffffff10 CS: 0010 SS: 0018 RIP: 00007f26017435c3 RSP: 00007fffe020c420 RFLAGS: 00000206 RAX: 0000000000000017 RBX: ffffffff8100b072 RCX: 00007fffe020c45c RDX: 00007f2604a3f120 RSI: 00007f2604a3f140 RDI: 000000000000000d RBP: 0000000000000000 R8: 00007fffe020e570 R9: 0101010101010101 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fffe020e5f0 R13: 00007fffe020e5f4 R14: 00007f26045f373c R15: 00007fffe020e5e0 ORIG_RAX: 0000000000000017 CS: 0033 SS: 002b Somewhere between the ata_sff_hsm_move() check and the ata_sff_host_intr() check, the value changed. On examining the other cpus to see what else was running, another cpu was running the error handler routines: PID: 326 TASK: ffff881c11014aa0 CPU: 1 COMMAND: "scsi_eh_1" #0 [ffff88008ba27e90] crash_nmi_callback at ffffffff8102fee6 #1 [ffff88008ba27ea0] notifier_call_chain at ffffffff8152d515 #2 [ffff88008ba27ee0] atomic_notifier_call_chain at ffffffff8152d57a #3 [ffff88008ba27ef0] notify_die at ffffffff810a154e #4 [ffff88008ba27f20] do_nmi at ffffffff8152b1db #5 [ffff88008ba27f50] nmi at ffffffff8152aaa0 [exception RIP: _spin_lock_irqsave+47] RIP: ffffffff8152a1ff RSP: ffff881c11a73aa0 RFLAGS: 00000006 RAX: 0000000000000001 RBX: ffff881c1121deb8 RCX: 0000000000000000 RDX: 0000000000000246 RSI: 0000000000000020 RDI: ffff881c122612d8 RBP: ffff881c11a73aa0 R8: ffff881c17083800 R9: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff881c1121c000 R13: 000000000000001f R14: ffff881c1121dd50 R15: ffff881c1121dc60 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0000 --- <NMI exception stack> --- #6 [ffff881c11a73aa0] _spin_lock_irqsave at ffffffff8152a1ff #7 [ffff881c11a73aa8] ata_exec_internal_sg at ffffffff81396fb5 #8 [ffff881c11a73b58] ata_exec_internal at ffffffff81397109 #9 [ffff881c11a73bd8] atapi_eh_request_sense at ffffffff813a34eb Before it tried to acquire a spinlock, ata_exec_internal_sg() called ata_sff_flush_pio_task(). This function will set ap->hsm_task_state to HSM_ST_IDLE, and has no locking around setting this value. ata_sff_flush_pio_task() can then race with the interrupt handler and potentially set HSM_ST_IDLE at a fatal moment, which will trigger a kernel BUG. v2: Fixup comment in ata_sff_flush_pio_task() tj: Further updated comment. Use ap->lock instead of shost lock and use the [un]lock_irq variant instead of the irqsave/restore one. Signed-off-by: David Milburn <dmilburn@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: stable@vger.kernel.org

commit ce75145 upstream. It is possible for ata_sff_flush_pio_task() to set ap->hsm_task_state to HSM_ST_IDLE in between the time __ata_sff_port_intr() checks for HSM_ST_IDLE and before it calls ata_sff_hsm_move() causing ata_sff_hsm_move() to BUG(). This problem is hard to reproduce making this patch hard to verify, but this fix will prevent the race. I have not been able to reproduce the problem, but here is a crash dump from a 2.6.32 kernel. On examining the ata port's state, its hsm_task_state field has a value of HSM_ST_IDLE: crash> struct ata_port.hsm_task_state ffff881c1121c000 hsm_task_state = 0 Normally, this should not be possible as ata_sff_hsm_move() was called from ata_sff_host_intr(), which checks hsm_task_state and won't call ata_sff_hsm_move() if it has a HSM_ST_IDLE value. PID: 11053 TASK: ffff8816e846cae0 CPU: 0 COMMAND: "sshd" #0 [ffff88008ba03960] machine_kexec at ffffffff81038f3b #1 [ffff88008ba039c0] crash_kexec at ffffffff810c5d92 #2 [ffff88008ba03a90] oops_end at ffffffff8152b510 #3 [ffff88008ba03ac0] die at ffffffff81010e0b #4 [ffff88008ba03af0] do_trap at ffffffff8152ad74 #5 [ffff88008ba03b50] do_invalid_op at ffffffff8100cf95 #6 [ffff88008ba03bf0] invalid_op at ffffffff8100bf9b [exception RIP: ata_sff_hsm_move+317] RIP: ffffffff813a77ad RSP: ffff88008ba03ca0 RFLAGS: 00010097 RAX: 0000000000000000 RBX: ffff881c1121dc60 RCX: 0000000000000000 RDX: ffff881c1121dd10 RSI: ffff881c1121dc60 RDI: ffff881c1121c000 RBP: ffff88008ba03d00 R8: 0000000000000000 R9: 000000000000002e R10: 000000000001003f R11: 000000000000009b R12: ffff881c1121c000 R13: 0000000000000000 R14: 0000000000000050 R15: ffff881c1121dd78 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 #7 [ffff88008ba03d08] ata_sff_host_intr at ffffffff813a7fbd #8 [ffff88008ba03d38] ata_sff_interrupt at ffffffff813a821e #9 [ffff88008ba03d78] handle_IRQ_event at ffffffff810e6ec0

Perf top raise a warning if a kernel sample is collected but kernel map is restricted. The warning message needs to dereference al.map->dso... However, previous perf_event__preprocess_sample() doesn't always guarantee al.map != NULL, for example, when kernel map is restricted. This patch validates al.map before dereferencing, avoid the segfault. Before this patch: $ cat /proc/sys/kernel/kptr_restrict 1 $ perf top -p 120183 perf: Segmentation fault -------- backtrace -------- /path/to/perf[0x509868] /lib64/libc.so.6(+0x3545f)[0x7f9a1540045f] /path/to/perf[0x448820] /path/to/perf(cmd_top+0xe3c)[0x44a5dc] /path/to/perf[0x4766a2] /path/to/perf(main+0x5f5)[0x42e545] /lib64/libc.so.6(__libc_start_main+0xf4)[0x7f9a153ecbd4] /path/to/perf[0x42e674] And gdb call trace: Program received signal SIGSEGV, Segmentation fault. perf_event__process_sample (machine=0xa44030, sample=0x7fffffffa4c0, evsel=0xa43b00, event=0x7ffff41c3000, tool=0x7fffffffa8a0) at builtin-top.c:736 736 !RB_EMPTY_ROOT(&al.map->dso->symbols[MAP__FUNCTION]) ? (gdb) bt #0 perf_event__process_sample (machine=0xa44030, sample=0x7fffffffa4c0, evsel=0xa43b00, event=0x7ffff41c3000, tool=0x7fffffffa8a0) at builtin-top.c:736 #1 perf_top__mmap_read_idx (top=top@entry=0x7fffffffa8a0, idx=idx@entry=0) at builtin-top.c:855 #2 0x000000000044a5dd in perf_top__mmap_read (top=0x7fffffffa8a0) at builtin-top.c:872 #3 __cmd_top (top=0x7fffffffa8a0) at builtin-top.c:997 #4 cmd_top (argc=<optimized out>, argv=<optimized out>, prefix=<optimized out>) at builtin-top.c:1267 #5 0x00000000004766a3 in run_builtin (p=p@entry=0x8a6ce8 <commands+264>, argc=argc@entry=3, argv=argv@entry=0x7fffffffdf70) at perf.c:371 #6 0x000000000042e546 in handle_internal_command (argv=0x7fffffffdf70, argc=3) at perf.c:430 #7 run_argv (argv=0x7fffffffdcf0, argcp=0x7fffffffdcfc) at perf.c:474 #8 main (argc=3, argv=0x7fffffffdf70) at perf.c:589 (gdb) Signed-off-by: Wang Nan <wangnan0@huawei.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: David Ahern <dsahern@gmail.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Zefan Li <lizefan@huawei.com> Link: http://lkml.kernel.org/r/1429946703-80807-1-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Page faults generated walking userspace stacks can call schedule to switch out the task. When collecting callchains for scheduler tracepoints this causes a deadlock as the tracepoints can be hit with the runqueue lock held: [ 8138.159054] WARNING: CPU: 758 PID: 12488 at /opt/dahern/linux.git/arch/sparc/kernel/nmi.c:80 perfctr_irq+0x1f8/0x2b4() [ 8138.203152] Watchdog detected hard LOCKUP on cpu 758 [ 8138.410969] CPU: 758 PID: 12488 Comm: perf Not tainted 4.0.0-rc6+ #6 [ 8138.437146] Call Trace: [ 8138.447193] [000000000045cdd4] warn_slowpath_common+0x7c/0xa0 [ 8138.471238] [000000000045ce90] warn_slowpath_fmt+0x30/0x40 [ 8138.494189] [0000000000983e38] perfctr_irq+0x1f8/0x2b4 [ 8138.515716] [00000000004209f4] tl0_irq15+0x14/0x20 [ 8138.535791] [00000000009839ec] _raw_spin_trylock_bh+0x68/0x108 [ 8138.560180] [0000000000980018] __schedule+0xcc/0x710 [ 8138.580981] [00000000009806dc] preempt_schedule_common+0x10/0x3c [ 8138.606082] [000000000098077c] _cond_resched+0x34/0x44 [ 8138.627603] [0000000000565990] kmem_cache_alloc_node+0x24/0x1a0 [ 8138.652345] [0000000000450b60] tsb_grow+0xac/0x488 [ 8138.672429] [0000000000985040] do_sparc64_fault+0x4dc/0x6e4 [ 8138.695736] [0000000000407c2c] sparc64_realfault_common+0x10/0x20 [ 8138.721202] [00000000006f2e24] NG4copy_from_user+0xa4/0x3c0 [ 8138.744510] [000000000044f900] perf_callchain_user+0x5c/0x6c [ 8138.768182] [0000000000517b5c] perf_callchain+0x16c/0x19c [ 8138.790774] [0000000000515f84] perf_prepare_sample+0x68/0x218 [ 8138.814801] ---[ end trace 42ca6294b1ff7573 ]--- As with PowerPC (b59a1bf, "powerpc/perf: Disable pagefaults during callchain stack read") disable pagefaults while walking userspace stacks. Signed-off-by: David Ahern <david.ahern@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>

Pagefault handling has a BUG_ON path that panics the system. Convert it to a warning instead. There is no need to bring down the system for this kind of failure. The following was hit while running: perf sched record -g -- make -j 16 [3609412.782801] kernel BUG at /opt/dahern/linux.git/arch/sparc/mm/fault_64.c:416! [3609412.782833] \|/ ____ \|/ [3609412.782833] "@'/ .. \`@" [3609412.782833] /_| \__/ |_\ [3609412.782833] \__U_/ [3609412.782870] cat(4516): Kernel bad sw trap 5 [#1] [3609412.782889] CPU: 0 PID: 4516 Comm: cat Tainted: G E 4.1.0-rc8+ #6 [3609412.782909] task: fff8000126e31f80 ti: fff8000110d90000 task.ti: fff8000110d90000 [3609412.782931] TSTATE: 0000004411001603 TPC: 000000000096b164 TNPC: 000000000096b168 Y: 0000004e Tainted: G E [3609412.782964] TPC: <do_sparc64_fault+0x5e4/0x6a0> [3609412.782979] g0: 000000000096abe0 g1: 0000000000d314c4 g2: 0000000000000000 g3: 0000000000000001 [3609412.783009] g4: fff8000126e31f80 g5: fff80001302d2000 g6: fff8000110d90000 g7: 00000000000000ff [3609412.783045] o0: 0000000000aff6a8 o1: 00000000000001a0 o2: 0000000000000001 o3: 0000000000000054 [3609412.783080] o4: fff8000100026820 o5: 0000000000000001 sp: fff8000110d935f1 ret_pc: 000000000096b15c [3609412.783117] RPC: <do_sparc64_fault+0x5dc/0x6a0> [3609412.783137] l0: 000007feff996000 l1: 0000000000030001 l2: 0000000000000004 l3: fff8000127bd0120 [3609412.783174] l4: 0000000000000054 l5: fff8000127bd0188 l6: 0000000000000000 l7: fff8000110d9dba8 [3609412.783210] i0: fff8000110d93f60 i1: fff8000110ca5530 i2: 000000000000003f i3: 0000000000000054 [3609412.783244] i4: fff800010000081a i5: fff8000100000398 i6: fff8000110d936a1 i7: 0000000000407c6c [3609412.783286] I7: <sparc64_realfault_common+0x10/0x20> [3609412.783308] Call Trace: [3609412.783329] [0000000000407c6c] sparc64_realfault_common+0x10/0x20 [3609412.783353] Disabling lock debugging due to kernel taint [3609412.783379] Caller[0000000000407c6c]: sparc64_realfault_common+0x10/0x20 [3609412.783449] Caller[fff80001002283e4]: 0xfff80001002283e4 [3609412.783471] Instruction DUMP: 921021a0 7feaff91 901222a8 <91d02005> 82086100 02f87f7b 808a2873 81cfe008 01000000 [3609412.783542] Kernel panic - not syncing: Fatal exception [3609412.784605] Press Stop-A (L1-A) to return to the boot prom [3609412.784615] ---[ end Kernel panic - not syncing: Fatal exception With this patch rather than a panic I occasionally get something like this: perf sched record -g -m 1024 -- make -j N where N is based on number of cpus (128 to 1024 for a T7-4 and 8 for an 8 cpu VM on a T5-2). WARNING: CPU: 211 PID: 52565 at /opt/dahern/linux.git/arch/sparc/mm/fault_64.c:417 do_sparc64_fault+0x340/0x70c() address (7feffcd6000) != regs->tpc (fff80001004873c0) Modules linked in: ipt_REJECT nf_reject_ipv4 nf_conntrack_ipv4 nf_defrag_ipv4 iptable_filter ip_tables ip6t_REJECT nf_reject_ipv6 xt_tcpudp nf_conntrack_ipv6 nf_defrag_ipv6 xt_state nf_conntrack ip6table_filter ip6_tables x_tables ipv6 cdc_ether usbnet mii ixgbe mdio igb i2c_algo_bit i2c_core ptp crc32c_sparc64 camellia_sparc64 des_sparc64 des_generic md5_sparc64 sha512_sparc64 sha1_sparc64 uio_pdrv_genirq uio usb_storage mpt3sas scsi_transport_sas raid_class aes_sparc64 sunvnet sunvdc sha256_sparc64(E) sha256_generic(E) CPU: 211 PID: 52565 Comm: ld Tainted: G W E 4.1.0-rc8+ #19 Call Trace: [000000000045ce30] warn_slowpath_common+0x7c/0xa0 [000000000045ceec] warn_slowpath_fmt+0x30/0x40 [000000000098ad64] do_sparc64_fault+0x340/0x70c [0000000000407c2c] sparc64_realfault_common+0x10/0x20 ---[ end trace 62ee02065a01a049 ]--- ld[52565]: segfault at fff80001004873c0 ip fff80001004873c0 (rpc fff8000100158868) sp 000007feffcd70e1 error 30002 in libc-2.12.so[fff8000100410000+184000] The segfault is horrible, but better than a system panic. An 8-cpu VM on a T5-2 also showed the above traces from time to time, so it is a general problem and not specific to the T7 or baremetal. Signed-off-by: David Ahern <david.ahern@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>

Nikolay has reported a hang when a memcg reclaim got stuck with the following backtrace: PID: 18308 TASK: ffff883d7c9b0a30 CPU: 1 COMMAND: "rsync" #0 __schedule at ffffffff815ab152 #1 schedule at ffffffff815ab76e #2 schedule_timeout at ffffffff815ae5e5 #3 io_schedule_timeout at ffffffff815aad6a #4 bit_wait_io at ffffffff815abfc6 #5 __wait_on_bit at ffffffff815abda5 #6 wait_on_page_bit at ffffffff8111fd4f #7 shrink_page_list at ffffffff81135445 #8 shrink_inactive_list at ffffffff81135845 #9 shrink_lruvec at ffffffff81135ead #10 shrink_zone at ffffffff811360c3 #11 shrink_zones at ffffffff81136eff #12 do_try_to_free_pages at ffffffff8113712f #13 try_to_free_mem_cgroup_pages at ffffffff811372be #14 try_charge at ffffffff81189423 #15 mem_cgroup_try_charge at ffffffff8118c6f5 #16 __add_to_page_cache_locked at ffffffff8112137d #17 add_to_page_cache_lru at ffffffff81121618 #18 pagecache_get_page at ffffffff8112170b #19 grow_dev_page at ffffffff811c8297 #20 __getblk_slow at ffffffff811c91d6 #21 __getblk_gfp at ffffffff811c92c1 #22 ext4_ext_grow_indepth at ffffffff8124565c #23 ext4_ext_create_new_leaf at ffffffff81246ca8 #24 ext4_ext_insert_extent at ffffffff81246f09 #25 ext4_ext_map_blocks at ffffffff8124a848 #26 ext4_map_blocks at ffffffff8121a5b7 #27 mpage_map_one_extent at ffffffff8121b1fa #28 mpage_map_and_submit_extent at ffffffff8121f07b #29 ext4_writepages at ffffffff8121f6d5 #30 do_writepages at ffffffff8112c490 #31 __filemap_fdatawrite_range at ffffffff81120199 #32 filemap_flush at ffffffff8112041c #33 ext4_alloc_da_blocks at ffffffff81219da1 #34 ext4_rename at ffffffff81229b91 #35 ext4_rename2 at ffffffff81229e32 #36 vfs_rename at ffffffff811a08a5 #37 SYSC_renameat2 at ffffffff811a3ffc #38 sys_renameat2 at ffffffff811a408e #39 sys_rename at ffffffff8119e51e #40 system_call_fastpath at ffffffff815afa89 Dave Chinner has properly pointed out that this is a deadlock in the reclaim code because ext4 doesn't submit pages which are marked by PG_writeback right away. The heuristic was introduced by commit e62e384 ("memcg: prevent OOM with too many dirty pages") and it was applied only when may_enter_fs was specified. The code has been changed by c3b94f4 ("memcg: further prevent OOM with too many dirty pages") which has removed the __GFP_FS restriction with a reasoning that we do not get into the fs code. But this is not sufficient apparently because the fs doesn't necessarily submit pages marked PG_writeback for IO right away. ext4_bio_write_page calls io_submit_add_bh but that doesn't necessarily submit the bio. Instead it tries to map more pages into the bio and mpage_map_one_extent might trigger memcg charge which might end up waiting on a page which is marked PG_writeback but hasn't been submitted yet so we would end up waiting for something that never finishes. Fix this issue by replacing __GFP_IO by may_enter_fs check (for case 2) before we go to wait on the writeback. The page fault path, which is the only path that triggers memcg oom killer since 3.12, shouldn't require GFP_NOFS and so we shouldn't reintroduce the premature OOM killer issue which was originally addressed by the heuristic. As per David Chinner the xfs is doing similar thing since 2.6.15 already so ext4 is not the only affected filesystem. Moreover he notes: : For example: IO completion might require unwritten extent conversion : which executes filesystem transactions and GFP_NOFS allocations. The : writeback flag on the pages can not be cleared until unwritten : extent conversion completes. Hence memory reclaim cannot wait on : page writeback to complete in GFP_NOFS context because it is not : safe to do so, memcg reclaim or otherwise. Cc: stable@vger.kernel.org # 3.9+ [tytso@mit.edu: corrected the control flow] Fixes: c3b94f4 ("memcg: further prevent OOM with too many dirty pages") Reported-by: Nikolay Borisov <kernel@kyup.com> Signed-off-by: Michal Hocko <mhocko@suse.cz> Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

It turns out that a PV domU also requires the "Xen PV" APIC driver. Otherwise, the flat driver is used and we get stuck in busy loops that never exit, such as in this stack trace: (gdb) target remote localhost:9999 Remote debugging using localhost:9999 __xapic_wait_icr_idle () at ./arch/x86/include/asm/ipi.h:56 56 while (native_apic_mem_read(APIC_ICR) & APIC_ICR_BUSY) (gdb) bt #0 __xapic_wait_icr_idle () at ./arch/x86/include/asm/ipi.h:56 #1 __default_send_IPI_shortcut (shortcut=<optimized out>, dest=<optimized out>, vector=<optimized out>) at ./arch/x86/include/asm/ipi.h:75 #2 apic_send_IPI_self (vector=246) at arch/x86/kernel/apic/probe_64.c:54 #3 0xffffffff81011336 in arch_irq_work_raise () at arch/x86/kernel/irq_work.c:47 #4 0xffffffff8114990c in irq_work_queue (work=0xffff88000fc0e400) at kernel/irq_work.c:100 #5 0xffffffff8110c29d in wake_up_klogd () at kernel/printk/printk.c:2633 #6 0xffffffff8110ca60 in vprintk_emit (facility=0, level=<optimized out>, dict=0x0 <irq_stack_union>, dictlen=<optimized out>, fmt=<optimized out>, args=<optimized out>) at kernel/printk/printk.c:1778 #7 0xffffffff816010c8 in printk (fmt=<optimized out>) at kernel/printk/printk.c:1868 #8 0xffffffffc00013ea in ?? () #9 0x0000000000000000 in ?? () Mailing-list-thread: https://lkml.org/lkml/2015/8/4/755 Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Cc: <stable@vger.kernel.org> Signed-off-by: David Vrabel <david.vrabel@citrix.com>

A recent change to the cpu_cooling code introduced a AB-BA deadlock scenario between the cpufreq_policy_notifier_list rwsem and the cooling_cpufreq_lock. This is caused by cooling_cpufreq_lock being held before the registration/removal of the notifier block (an operation which takes the rwsem), and the notifier code itself which takes the locks in the reverse order: ====================================================== [ INFO: possible circular locking dependency detected ] 3.18.0+ #1453 Not tainted ------------------------------------------------------- rc.local/770 is trying to acquire lock: (cooling_cpufreq_lock){+.+.+.}, at: [<c04abfc4>] cpufreq_thermal_notifier+0x34/0xfc but task is already holding lock: ((cpufreq_policy_notifier_list).rwsem){++++.+}, at: [<c0042f04>] __blocking_notifier_call_chain+0x34/0x68 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 ((cpufreq_policy_notifier_list).rwsem){++++.+}: [<c06bc3b0>] down_write+0x44/0x9c [<c0043444>] blocking_notifier_chain_register+0x28/0xd8 [<c04ad610>] cpufreq_register_notifier+0x68/0x90 [<c04abe4c>] __cpufreq_cooling_register.part.1+0x120/0x180 [<c04abf44>] __cpufreq_cooling_register+0x98/0xa4 [<c04abf8c>] cpufreq_cooling_register+0x18/0x1c [<bf0046f8>] imx_thermal_probe+0x1c0/0x470 [imx_thermal] [<c037cef8>] platform_drv_probe+0x50/0xac [<c037b710>] driver_probe_device+0x114/0x234 [<c037b8cc>] __driver_attach+0x9c/0xa0 [<c0379d68>] bus_for_each_dev+0x5c/0x90 [<c037b204>] driver_attach+0x24/0x28 [<c037ae7c>] bus_add_driver+0xe0/0x1d8 [<c037c0cc>] driver_register+0x80/0xfc [<c037cd80>] __platform_driver_register+0x50/0x64 [<bf007018>] 0xbf007018 [<c0008a5c>] do_one_initcall+0x88/0x1d8 [<c0095da4>] load_module+0x1768/0x1ef8 [<c0096614>] SyS_init_module+0xe0/0xf4 [<c000ec00>] ret_fast_syscall+0x0/0x48 -> #0 (cooling_cpufreq_lock){+.+.+.}: [<c00619f8>] lock_acquire+0xb0/0x124 [<c06ba3b4>] mutex_lock_nested+0x5c/0x3d8 [<c04abfc4>] cpufreq_thermal_notifier+0x34/0xfc [<c0042bf4>] notifier_call_chain+0x4c/0x8c [<c0042f20>] __blocking_notifier_call_chain+0x50/0x68 [<c0042f58>] blocking_notifier_call_chain+0x20/0x28 [<c04ae62c>] cpufreq_set_policy+0x7c/0x1d0 [<c04af3cc>] store_scaling_governor+0x74/0x9c [<c04ad418>] store+0x90/0xc0 [<c0175384>] sysfs_kf_write+0x54/0x58 [<c01746b4>] kernfs_fop_write+0xdc/0x190 [<c010dcc0>] vfs_write+0xac/0x1b4 [<c010dfec>] SyS_write+0x44/0x90 [<c000ec00>] ret_fast_syscall+0x0/0x48 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock((cpufreq_policy_notifier_list).rwsem); lock(cooling_cpufreq_lock); lock((cpufreq_policy_notifier_list).rwsem); lock(cooling_cpufreq_lock); *** DEADLOCK *** 7 locks held by rc.local/770: #0: (sb_writers#6){.+.+.+}, at: [<c010dda0>] vfs_write+0x18c/0x1b4 #1: (&of->mutex){+.+.+.}, at: [<c0174678>] kernfs_fop_write+0xa0/0x190 #2: (s_active#52){.+.+.+}, at: [<c0174680>] kernfs_fop_write+0xa8/0x190 #3: (cpu_hotplug.lock){++++++}, at: [<c0026a60>] get_online_cpus+0x34/0x90 #4: (cpufreq_rwsem){.+.+.+}, at: [<c04ad3e0>] store+0x58/0xc0 #5: (&policy->rwsem){+.+.+.}, at: [<c04ad3f8>] store+0x70/0xc0 #6: ((cpufreq_policy_notifier_list).rwsem){++++.+}, at: [<c0042f04>] __blocking_notifier_call_chain+0x34/0x68 stack backtrace: CPU: 0 PID: 770 Comm: rc.local Not tainted 3.18.0+ #1453 Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree) Backtrace: [<c00121c8>] (dump_backtrace) from [<c0012360>] (show_stack+0x18/0x1c) r6:c0b85a80 r5:c0b75630 r4:00000000 r3:00000000 [<c0012348>] (show_stack) from [<c06b6c48>] (dump_stack+0x7c/0x98) [<c06b6bcc>] (dump_stack) from [<c06b42a4>] (print_circular_bug+0x28c/0x2d8) r4:c0b85a80 r3:d0071d40 [<c06b4018>] (print_circular_bug) from [<c00613b0>] (__lock_acquire+0x1acc/0x1bb0) r10:c0b50660 r8:c09e6d80 r7:d0071d40 r6:c11d0f0c r5:00000007 r4:d0072240 [<c005f8e4>] (__lock_acquire) from [<c00619f8>] (lock_acquire+0xb0/0x124) r10:00000000 r9:c04abfc4 r8:00000000 r7:00000000 r6:00000000 r5:c0a06f0c r4:00000000 [<c0061948>] (lock_acquire) from [<c06ba3b4>] (mutex_lock_nested+0x5c/0x3d8) r10:ec853800 r9:c0a06ed4 r8:d0071d40 r7:c0a06ed4 r6:c11d0f0c r5:00000000 r4:c04abfc4 [<c06ba358>] (mutex_lock_nested) from [<c04abfc4>] (cpufreq_thermal_notifier+0x34/0xfc) r10:ec853800 r9:ec85380c r8:d00d7d3c r7:c0a06ed4 r6:d00d7d3c r5:00000000 r4:fffffffe [<c04abf90>] (cpufreq_thermal_notifier) from [<c0042bf4>] (notifier_call_chain+0x4c/0x8c) r7:00000000 r6:00000000 r5:00000000 r4:fffffffe [<c0042ba8>] (notifier_call_chain) from [<c0042f20>] (__blocking_notifier_call_chain+0x50/0x68) r8:c0a072a4 r7:00000000 r6:d00d7d3c r5:ffffffff r4:c0a06fc8 r3:ffffffff [<c0042ed0>] (__blocking_notifier_call_chain) from [<c0042f58>] (blocking_notifier_call_chain+0x20/0x28) r7:ec98b540 r6:c13ebc80 r5:ed76e600 r4:d00d7d3c [<c0042f38>] (blocking_notifier_call_chain) from [<c04ae62c>] (cpufreq_set_policy+0x7c/0x1d0) [<c04ae5b0>] (cpufreq_set_policy) from [<c04af3cc>] (store_scaling_governor+0x74/0x9c) r7:ec98b540 r6:0000000c r5:ec98b540 r4:ed76e600 [<c04af358>] (store_scaling_governor) from [<c04ad418>] (store+0x90/0xc0) r6:0000000c r5:ed76e6d4 r4:ed76e600 [<c04ad388>] (store) from [<c0175384>] (sysfs_kf_write+0x54/0x58) r8:0000000c r7:d00d7f78 r6:ec98b540 r5:0000000c r4:ec853800 r3:0000000c [<c0175330>] (sysfs_kf_write) from [<c01746b4>] (kernfs_fop_write+0xdc/0x190) r6:ec98b540 r5:00000000 r4:00000000 r3:c0175330 [<c01745d8>] (kernfs_fop_write) from [<c010dcc0>] (vfs_write+0xac/0x1b4) r10:0162aa70 r9:d00d6000 r8:0000000c r7:d00d7f78 r6:0162aa70 r5:0000000c r4:eccde500 [<c010dc14>] (vfs_write) from [<c010dfec>] (SyS_write+0x44/0x90) r10:0162aa70 r8:0000000c r7:eccde500 r6:eccde500 r5:00000000 r4:00000000 [<c010dfa8>] (SyS_write) from [<c000ec00>] (ret_fast_syscall+0x0/0x48) r10:00000000 r8:c000edc4 r7:00000004 r6:000216cc r5:0000000c r4:0162aa70 Solve this by moving to finer grained locking - use one mutex to protect the cpufreq_dev_list as a whole, and a separate lock to ensure correct ordering of cpufreq notifier registration and removal. cooling_list_lock is taken within cooling_cpufreq_lock on (un)registration to preserve the behavior of the code, i.e. to atomically add/remove to the list and (un)register the notifier. Fixes: 2dcd851 ("thermal: cpu_cooling: Update always cpufreq policy with Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Eduardo Valentin <edubezval@gmail.com>

PID: 614 TASK: ffff882a739da580 CPU: 3 COMMAND: "ocfs2dc" #0 [ffff882ecc3759b0] machine_kexec at ffffffff8103b35d #1 [ffff882ecc375a20] crash_kexec at ffffffff810b95b5 #2 [ffff882ecc375af0] oops_end at ffffffff815091d8 #3 [ffff882ecc375b20] die at ffffffff8101868b #4 [ffff882ecc375b50] do_trap at ffffffff81508bb0 #5 [ffff882ecc375ba0] do_invalid_op at ffffffff810165e5 #6 [ffff882ecc375c40] invalid_op at ffffffff815116fb [exception RIP: ocfs2_ci_checkpointed+208] RIP: ffffffffa0a7e940 RSP: ffff882ecc375cf0 RFLAGS: 00010002 RAX: 0000000000000001 RBX: 000000000000654b RCX: ffff8812dc83f1f8 RDX: 00000000000017d9 RSI: ffff8812dc83f1f8 RDI: ffffffffa0b2c318 RBP: ffff882ecc375d20 R8: ffff882ef6ecfa60 R9: ffff88301f272200 R10: 0000000000000000 R11: 0000000000000000 R12: ffffffffffffffff R13: ffff8812dc83f4f0 R14: 0000000000000000 R15: ffff8812dc83f1f8 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 #7 [ffff882ecc375d28] ocfs2_check_meta_downconvert at ffffffffa0a7edbd [ocfs2] #8 [ffff882ecc375d38] ocfs2_unblock_lock at ffffffffa0a84af8 [ocfs2] #9 [ffff882ecc375dc8] ocfs2_process_blocked_lock at ffffffffa0a85285 [ocfs2] #10 [ffff882ecc375e18] ocfs2_downconvert_thread_do_work at ffffffffa0a85445 [ocfs2] #11 [ffff882ecc375e68] ocfs2_downconvert_thread at ffffffffa0a854de [ocfs2] #12 [ffff882ecc375ee8] kthread at ffffffff81090da7 #13 [ffff882ecc375f48] kernel_thread_helper at ffffffff81511884 assert is tripped because the tran is not checkpointed and the lock level is PR. Some time ago, chmod command had been executed. As result, the following call chain left the inode cluster lock in PR state, latter on causing the assert. system_call_fastpath -> my_chmod -> sys_chmod -> sys_fchmodat -> notify_change -> ocfs2_setattr -> posix_acl_chmod -> ocfs2_iop_set_acl -> ocfs2_set_acl -> ocfs2_acl_set_mode Here is how. 1119 int ocfs2_setattr(struct dentry *dentry, struct iattr *attr) 1120 { 1247 ocfs2_inode_unlock(inode, 1); <<< WRONG thing to do. .. 1258 if (!status && attr->ia_valid & ATTR_MODE) { 1259 status = posix_acl_chmod(inode, inode->i_mode); 519 posix_acl_chmod(struct inode *inode, umode_t mode) 520 { .. 539 ret = inode->i_op->set_acl(inode, acl, ACL_TYPE_ACCESS); 287 int ocfs2_iop_set_acl(struct inode *inode, struct posix_acl *acl, ... 288 { 289 return ocfs2_set_acl(NULL, inode, NULL, type, acl, NULL, NULL); 224 int ocfs2_set_acl(handle_t *handle, 225 struct inode *inode, ... 231 { .. 252 ret = ocfs2_acl_set_mode(inode, di_bh, 253 handle, mode); 168 static int ocfs2_acl_set_mode(struct inode *inode, struct buffer_head ... 170 { 183 if (handle == NULL) { >>> BUG: inode lock not held in ex at this point <<< 184 handle = ocfs2_start_trans(OCFS2_SB(inode->i_sb), 185 OCFS2_INODE_UPDATE_CREDITS); ocfs2_setattr.#1247 we unlock and at #1259 call posix_acl_chmod. When we reach ocfs2_acl_set_mode.#181 and do trans, the inode cluster lock is not held in EX mode (it should be). How this could have happended? We are the lock master, were holding lock EX and have released it in ocfs2_setattr.#1247. Note that there are no holders of this lock at this point. Another node needs the lock in PR, and we downconvert from EX to PR. So the inode lock is PR when do the trans in ocfs2_acl_set_mode.#184. The trans stays in core (not flushed to disc). Now another node want the lock in EX, downconvert thread gets kicked (the one that tripped assert abovt), finds an unflushed trans but the lock is not EX (it is PR). If the lock was at EX, it would have flushed the trans ocfs2_ci_checkpointed -> ocfs2_start_checkpoint before downconverting (to NULL) for the request. ocfs2_setattr must not drop inode lock ex in this code path. If it does, takes it again before the trans, say in ocfs2_set_acl, another cluster node can get in between, execute another setattr, overwriting the one in progress on this node, resulting in a mode acl size combo that is a mix of the two. Orabug: 20189959 Signed-off-by: Tariq Saeed <tariq.x.saeed@oracle.com> Reviewed-by: Mark Fasheh <mfasheh@suse.de> Cc: Joel Becker <jlbec@evilplan.org> Cc: Joseph Qi <joseph.qi@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Commit b1c9f169047b ("xen: split counting of extra memory pages...") introduced an error when dom0 was started with limited memory. The problem arises in case dom0 is started with initial memory and maximum memory being the same and exactly a multiple of 1 GB. The kernel must be configured without CONFIG_XEN_BALLOON_MEMORY_HOTPLUG for the problem to happen. In this case it will crash very early during boot due to the virtual mapped p2m list not being large enough to be able to remap any memory: (XEN) Freed 304kB init memory. mapping kernel into physical memory about to get started... (XEN) traps.c:459:d0v0 Unhandled invalid opcode fault/trap [#6] on VCPU 0 [ec=0000] (XEN) domain_crash_sync called from entry.S: fault at ffff82d080229a93 create_bounce_frame+0x12b/0x13a (XEN) Domain 0 (vcpu#0) crashed on cpu#0: (XEN) ----[ Xen-4.5.2-pre x86_64 debug=n Not tainted ]---- (XEN) CPU: 0 (XEN) RIP: e033:[<ffffffff81d120cb>] (XEN) RFLAGS: 0000000000000206 EM: 1 CONTEXT: pv guest (d0v0) (XEN) rax: ffffffff81db2000 rbx: 000000004d000000 rcx: 0000000000000000 (XEN) rdx: 000000004d000000 rsi: 0000000000063000 rdi: 000000004d063000 (XEN) rbp: ffffffff81c03d78 rsp: ffffffff81c03d28 r8: 0000000000023000 (XEN) r9: 00000001040ff000 r10: 0000000000007ff0 r11: 0000000000000000 (XEN) r12: 0000000000063000 r13: 000000000004d000 r14: 0000000000000063 (XEN) r15: 0000000000000063 cr0: 0000000080050033 cr4: 00000000000006f0 (XEN) cr3: 0000000105c0f000 cr2: ffffc90000268000 (XEN) ds: 0000 es: 0000 fs: 0000 gs: 0000 ss: e02b cs: e033 (XEN) Guest stack trace from rsp=ffffffff81c03d28: (XEN) 0000000000000000 0000000000000000 ffffffff81d120cb 000000010000e030 (XEN) 0000000000010006 ffffffff81c03d68 000000000000e02b ffffffffffffffff (XEN) 0000000000000063 000000000004d063 ffffffff81c03de8 ffffffff81d130a7 (XEN) ffffffff81c03de8 000000000004d000 00000001040ff000 0000000000105db1 (XEN) 00000001040ff001 000000000004d062 ffff8800092d6ff8 0000000002027000 (XEN) ffff8800094d8340 ffff8800092d6ff8 00003ffffffff000 ffff8800092d7ff8 (XEN) ffffffff81c03e48 ffffffff81d13c43 ffff8800094d8000 ffff8800094d9000 (XEN) 0000000000000000 ffff8800092d6000 00000000092d6000 000000004cfbf000 (XEN) 00000000092d6000 00000000052d5442 0000000000000000 0000000000000000 (XEN) ffffffff81c03ed8 ffffffff81d185c1 0000000000000000 0000000000000000 (XEN) ffffffff81c03e78 ffffffff810f8ca4 ffffffff81c03ed8 ffffffff8171a15d (XEN) 0000000000000010 ffffffff81c03ee8 0000000000000000 0000000000000000 (XEN) ffffffff81f0e402 ffffffffffffffff ffffffff81dae900 0000000000000000 (XEN) 0000000000000000 0000000000000000 ffffffff81c03f28 ffffffff81d0cf0f (XEN) 0000000000000000 0000000000000000 0000000000000000 ffffffff81db82e0 (XEN) 0000000000000000 0000000000000000 0000000000000000 0000000000000000 (XEN) ffffffff81c03f38 ffffffff81d0c603 ffffffff81c03ff8 ffffffff81d11c86 (XEN) 0300000100000032 0000000000000005 0000000000000020 0000000000000000 (XEN) 0000000000000000 0000000000000000 0000000000000000 0000000000000000 (XEN) 0000000000000000 0000000000000000 0000000000000000 0000000000000000 (XEN) Domain 0 crashed: rebooting machine in 5 seconds. This can be avoided by allocating aneough space for the p2m to cover the maximum memory of dom0 plus the identity mapped holes required for PCI space, BIOS etc. Reported-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>

Commit e0e8173 ("CRED: Add some configurable debugging [try #6]") added the kdebug mechanism to this file back in 2009. The kdebug macro calls no_printk which always evaluates arguments. Most of the kdebug uses have an unnecessary call of atomic_read(&cred->usage) Make the kdebug macro do nothing by defining it with do { if (0) no_printk(...); } while (0) when not enabled. $ size kernel/cred.o* (defconfig x86-64) text data bss dec hex filename 2748 336 8 3092 c14 kernel/cred.o.new 2788 336 8 3132 c3c kernel/cred.o.old Miscellanea: o Neaten the #define kdebug macros while there Signed-off-by: Joe Perches <joe@perches.com> Cc: David Howells <dhowells@redhat.com> Cc: James Morris <jmorris@namei.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The renesas-intc-irqpin interrupt controller is cascaded to the GIC. Hence when propagating wake-up settings to its parent interrupt controller, the following lockdep warning is printed: ============================================= [ INFO: possible recursive locking detected ] 4.2.0-armadillo-10725-g50fcd7643c034198 #781 Not tainted --------------------------------------------- s2ram/1179 is trying to acquire lock: (&irq_desc_lock_class){-.-...}, at: [<c005bb54>] __irq_get_desc_lock+0x78/0x94 but task is already holding lock: (&irq_desc_lock_class){-.-...}, at: [<c005bb54>] __irq_get_desc_lock+0x78/0x94 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&irq_desc_lock_class); lock(&irq_desc_lock_class); *** DEADLOCK *** May be due to missing lock nesting notation 7 locks held by s2ram/1179: #0: (sb_writers#7){.+.+.+}, at: [<c00c9708>] __sb_start_write+0x64/0xb8 #1: (&of->mutex){+.+.+.}, at: [<c0125a00>] kernfs_fop_write+0x78/0x1a0 #2: (s_active#23){.+.+.+}, at: [<c0125a08>] kernfs_fop_write+0x80/0x1a0 #3: (autosleep_lock){+.+.+.}, at: [<c0058244>] pm_autosleep_lock+0x18/0x20 #4: (pm_mutex){+.+.+.}, at: [<c0057e50>] pm_suspend+0x54/0x248 #5: (&dev->mutex){......}, at: [<c0243a20>] __device_suspend+0xdc/0x240 #6: (&irq_desc_lock_class){-.-...}, at: [<c005bb54>] __irq_get_desc_lock+0x78/0x94 stack backtrace: CPU: 0 PID: 1179 Comm: s2ram Not tainted 4.2.0-armadillo-10725-g50fcd7643c034198 Hardware name: Generic R8A7740 (Flattened Device Tree) [<c00129f4>] (dump_backtrace) from [<c0012bec>] (show_stack+0x18/0x1c) [<c0012bd4>] (show_stack) from [<c03f5d94>] (dump_stack+0x20/0x28) [<c03f5d74>] (dump_stack) from [<c00514d4>] (__lock_acquire+0x67c/0x1b88) [<c0050e58>] (__lock_acquire) from [<c0052df8>] (lock_acquire+0x9c/0xbc) [<c0052d5c>] (lock_acquire) from [<c03fb068>] (_raw_spin_lock_irqsave+0x44/0x58) [<c03fb024>] (_raw_spin_lock_irqsave) from [<c005bb54>] (__irq_get_desc_lock+0x78/0x94 [<c005badc>] (__irq_get_desc_lock) from [<c005c3d8>] (irq_set_irq_wake+0x28/0x100) [<c005c3b0>] (irq_set_irq_wake) from [<c01e50d0>] (intc_irqpin_irq_set_wake+0x24/0x4c) [<c01e50ac>] (intc_irqpin_irq_set_wake) from [<c005c17c>] (set_irq_wake_real+0x3c/0x50 [<c005c140>] (set_irq_wake_real) from [<c005c414>] (irq_set_irq_wake+0x64/0x100) [<c005c3b0>] (irq_set_irq_wake) from [<c02a19b4>] (gpio_keys_suspend+0x60/0xa0) [<c02a1954>] (gpio_keys_suspend) from [<c023b750>] (platform_pm_suspend+0x3c/0x5c) Avoid this false positive by using a separate lockdep class for INTC External IRQ Pin interrupts. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Cc: Grygorii Strashko <grygorii.strashko@ti.com> Cc: Magnus Damm <magnus.damm@gmail.com> Cc: Jason Cooper <jason@lakedaemon.net> Link: http://lkml.kernel.org/r/1441798974-25716-3-git-send-email-geert%2Brenesas@glider.be Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

My colleague ran into a program stall on a x86_64 server, where n_tty_read() was waiting for data even if there was data in the buffer in the pty. kernel stack for the stuck process looks like below. #0 [ffff88303d107b58] __schedule at ffffffff815c4b20 #1 [ffff88303d107bd0] schedule at ffffffff815c513e #2 [ffff88303d107bf0] schedule_timeout at ffffffff815c7818 #3 [ffff88303d107ca0] wait_woken at ffffffff81096bd2 #4 [ffff88303d107ce0] n_tty_read at ffffffff8136fa23 #5 [ffff88303d107dd0] tty_read at ffffffff81368013 #6 [ffff88303d107e20] __vfs_read at ffffffff811a3704 #7 [ffff88303d107ec0] vfs_read at ffffffff811a3a57 #8 [ffff88303d107f00] sys_read at ffffffff811a4306 #9 [ffff88303d107f50] entry_SYSCALL_64_fastpath at ffffffff815c86d7 There seems to be two problems causing this issue. First, in drivers/tty/n_tty.c, __receive_buf() stores the data and updates ldata->commit_head using smp_store_release() and then checks the wait queue using waitqueue_active(). However, since there is no memory barrier, __receive_buf() could return without calling wake_up_interactive_poll(), and at the same time, n_tty_read() could start to wait in wait_woken() as in the following chart. __receive_buf() n_tty_read() ------------------------------------------------------------------------ if (waitqueue_active(&tty->read_wait)) /* Memory operations issued after the RELEASE may be completed before the RELEASE operation has completed */ add_wait_queue(&tty->read_wait, &wait); ... if (!input_available_p(tty, 0)) { smp_store_release(&ldata->commit_head, ldata->read_head); ... timeout = wait_woken(&wait, TASK_INTERRUPTIBLE, timeout); ------------------------------------------------------------------------ The second problem is that n_tty_read() also lacks a memory barrier call and could also cause __receive_buf() to return without calling wake_up_interactive_poll(), and n_tty_read() to wait in wait_woken() as in the chart below. __receive_buf() n_tty_read() ------------------------------------------------------------------------ spin_lock_irqsave(&q->lock, flags); /* from add_wait_queue() */ ... if (!input_available_p(tty, 0)) { /* Memory operations issued after the RELEASE may be completed before the RELEASE operation has completed */ smp_store_release(&ldata->commit_head, ldata->read_head); if (waitqueue_active(&tty->read_wait)) __add_wait_queue(q, wait); spin_unlock_irqrestore(&q->lock,flags); /* from add_wait_queue() */ ... timeout = wait_woken(&wait, TASK_INTERRUPTIBLE, timeout); ------------------------------------------------------------------------ There are also other places in drivers/tty/n_tty.c which have similar calls to waitqueue_active(), so instead of adding many memory barrier calls, this patch simply removes the call to waitqueue_active(), leaving just wake_up*() behind. This fixes both problems because, even though the memory access before or after the spinlocks in both wake_up*() and add_wait_queue() can sneak into the critical section, it cannot go past it and the critical section assures that they will be serialized (please see "INTER-CPU ACQUIRING BARRIER EFFECTS" in Documentation/memory-barriers.txt for a better explanation). Moreover, the resulting code is much simpler. Latency measurement using a ping-pong test over a pty doesn't show any visible performance drop. Signed-off-by: Kosuke Tatsukawa <tatsu@ab.jp.nec.com> Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

If an atomic update fails intel_crtc->atomic may have have some values left from the last atomic check. One example is atomic->wait_for_vblank, which results in spurious errors in kms_flip. [ 1551.892708] ------------[ cut here ]------------ [ 1551.892721] WARNING: CPU: 3 PID: 4179 at ../drivers/gpu/drm/drm_irq.c:1199 drm_wait_one_vblank+0x197/0x1a0 [drm]() [ 1551.892722] vblank not available on crtc 2, ret=-22 [ 1551.892751] Modules linked in: snd_hda_intel i915 drm_kms_helper drm intel_gtt i2c_algo_bit cfbfillrect syscopyarea cfbimgblt sysfillrect sysimgblt fb_sys_fops cfbcopyarea agpgart cfg80211 binfmt_misc snd_hda_codec_hdmi intel_rapl iosf_mbi x86_pkg_temp_thermal coretemp kvm_intel snd_hda_codec_realtek kvm snd_hda_codec_generic iTCO_wdt aesni_intel aes_x86_64 glue_helper lrw snd_hda_codec gf128mul ablk_helper cryptd snd_hwdep psmouse snd_hda_core pcspkr snd_pcm snd_timer snd lpc_ich i2c_i801 mfd_core soundcore wmi evdev [last unloaded: drm] [ 1551.892753] CPU: 3 PID: 4179 Comm: kms_pipe_crc_ba Tainted: G U W 4.3.0-reg+ #6 [ 1551.892754] Hardware name: /DZ77BH-55K, BIOS BHZ7710H.86A.0100.2013.0517.0942 05/17/2013 [ 1551.892758] ffffffffa03128d8 ffff8800cec73890 ffffffff812c0f3c ffff8800cec738d8 [ 1551.892760] ffff8800cec738c8 ffffffff8104ff36 ffff880116ae2290 0000000000000002 [ 1551.892762] ffff8800d39fcda0 ffff8800d038b4d0 ffff8800d42b5550 ffff8800cec73928 [ 1551.892763] Call Trace: [ 1551.892768] [<ffffffff812c0f3c>] dump_stack+0x4e/0x82 [ 1551.892771] [<ffffffff8104ff36>] warn_slowpath_common+0x86/0xc0 [ 1551.892773] [<ffffffff8104ffbc>] warn_slowpath_fmt+0x4c/0x50 [ 1551.892781] [<ffffffffa02e6708>] ? drm_vblank_get+0x78/0xd0 [drm] [ 1551.892787] [<ffffffffa02e6d47>] drm_wait_one_vblank+0x197/0x1a0 [drm] [ 1551.892813] [<ffffffffa03d052f>] intel_post_plane_update+0xef/0x120 [i915] [ 1551.892832] [<ffffffffa03d11d2>] intel_atomic_commit+0x4c2/0x1600 [i915] [ 1551.892862] [<ffffffffa02ff0c7>] ? drm_atomic_check_only+0x147/0x5e0 [drm] [ 1551.892872] [<ffffffffa02feeb7>] ? drm_atomic_add_affected_connectors+0x27/0xf0 [drm] [ 1551.892881] [<ffffffffa02ff597>] drm_atomic_commit+0x37/0x60 [drm] [ 1551.892887] [<ffffffffa034301a>] restore_fbdev_mode+0x28a/0x2c0 [drm_kms_helper] [ 1551.892895] [<ffffffffa0345253>] drm_fb_helper_restore_fbdev_mode_unlocked+0x33/0x80 [drm_kms_helper] [ 1551.892900] [<ffffffffa03452cd>] drm_fb_helper_set_par+0x2d/0x50 [drm_kms_helper] [ 1551.892920] [<ffffffffa03e7a9a>] intel_fbdev_set_par+0x1a/0x60 [i915] [ 1551.892923] [<ffffffff8131a5a7>] fb_set_var+0x1a7/0x3f0 [ 1551.892927] [<ffffffff8109732f>] ? trace_hardirqs_on_caller+0x12f/0x1c0 [ 1551.892931] [<ffffffff81314f32>] fbcon_blank+0x212/0x2f0 [ 1551.892935] [<ffffffff81373f4a>] do_unblank_screen+0xba/0x1d0 [ 1551.892937] [<ffffffff8136b725>] vt_ioctl+0x13d5/0x1450 [ 1551.892940] [<ffffffff8107cdd1>] ? preempt_count_sub+0x41/0x50 [ 1551.892943] [<ffffffff8135d8a3>] tty_ioctl+0x423/0xe30 [ 1551.892947] [<ffffffff8119f721>] do_vfs_ioctl+0x301/0x560 [ 1551.892949] [<ffffffff8119b1e3>] ? putname+0x53/0x60 [ 1551.892952] [<ffffffff811ab376>] ? __fget_light+0x66/0x90 [ 1551.892955] [<ffffffff8119f9f9>] SyS_ioctl+0x79/0x90 [ 1551.892958] [<ffffffff81552e97>] entry_SYSCALL_64_fastpath+0x12/0x6f [ 1551.892961] ---[ end trace 3e764d4b6628c91c ]--- Testcase: kms_flip Reported-and-tested-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: stable@vger.kernel.org #v4.3 Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Reviewed-by: Daniel Stone <daniels@collabora.com> Signed-off-by: Jani Nikula <jani.nikula@intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/5649C2BA.6080300@mblankhorst.nl

We try to convert the old way of of specifying fb tiling (obj->tiling) into the new fb modifiers. We store the result in the passed in mode_cmd structure. But that structure comes directly from the addfb2 ioctl, and gets copied back out to userspace, which means we're clobbering the modifiers that the user provided (all 0 since the DRM_MODE_FB_MODIFIERS flag wasn't even set by the user). Hence if the user reuses the struct for another addfb2, the ioctl will be rejected since it's now asking for some modifiers w/o the flag set. Fix the problem by making a copy of the user provided structure. We can play any games we want with the copy. IGT-Version: 1.12-git (x86_64) (Linux: 4.4.0-rc1-stereo+ x86_64) ... Subtest basic-X-tiled: SUCCESS (0.001s) Test assertion failure function pitch_tests, file kms_addfb_basic.c:167: Failed assertion: drmIoctl(fd, DRM_IOCTL_MODE_ADDFB2, &f) == 0 Last errno: 22, Invalid argument Stack trace: #0 [__igt_fail_assert+0x101] #1 [pitch_tests+0x619] #2 [__real_main426+0x2f] #3 [main+0x23] #4 [__libc_start_main+0xf0] #5 [_start+0x29] #6 [<unknown>+0x29] Subtest framebuffer-vs-set-tiling failed. **** DEBUG **** Test assertion failure function pitch_tests, file kms_addfb_basic.c:167: Failed assertion: drmIoctl(fd, DRM_IOCTL_MODE_ADDFB2, &f) == 0 Last errno: 22, Invalid argument **** END **** Subtest framebuffer-vs-set-tiling: FAIL (0.003s) ... IGT-Version: 1.12-git (x86_64) (Linux: 4.4.0-rc1-stereo+ x86_64) Subtest framebuffer-vs-set-tiling: SUCCESS (0.000s) Cc: stable@vger.kernel.org # v4.1+ Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Fixes: 2a80ead ("drm/i915: Add fb format modifier support") Testcase: igt/kms_addfb_basic/clobbered-modifier Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Jani Nikula <jani.nikula@intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1447261890-3960-1-git-send-email-ville.syrjala@linux.intel.com

The machine hang completely with the following message on the console: [ 487.777538] BUG: unable to handle kernel NULL pointer dereference at 0000000000000060 [ 487.777554] IP: [<ffffffff8158aaee>] _raw_spin_lock+0xe/0x30 [ 487.777557] PGD 42e9f7067 PUD 42f2fa067 PMD 0 [ 487.777560] Oops: 0002 [#1] SMP ... [ 487.777618] CPU: 21 PID: 3190 Comm: Xorg Tainted: G E 4.4.0-rc1-3-default+ #6 [ 487.777620] Hardware name: Intel Corporation BRICKLAND/BRICKLAND, BIOS BRHSXSD1.86B.0059.R00.1501081238 01/08/2015 [ 487.777621] task: ffff880853ae4680 ti: ffff8808696d4000 task.ti: ffff8808696d4000 [ 487.777625] RIP: 0010:[<ffffffff8158aaee>] [<ffffffff8158aaee>] _raw_spin_lock+0xe/0x30 [ 487.777627] RSP: 0018:ffff8808696d79c0 EFLAGS: 00010246 [ 487.777628] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 [ 487.777629] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000060 [ 487.777630] RBP: ffff8808696d79e0 R08: 0000000000000000 R09: ffff88086924a780 [ 487.777631] R10: 000000000001bb40 R11: 0000000000003246 R12: 0000000000000000 [ 487.777632] R13: ffff880463a27360 R14: ffff88046ca50218 R15: 0000000000000080 [ 487.777634] FS: 00007f3f81c5a8c0(0000) GS:ffff88086f060000(0000) knlGS:0000000000000000 [ 487.777635] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 487.777636] CR2: 0000000000000060 CR3: 000000042e678000 CR4: 00000000001406e0 [ 487.777638] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 487.777639] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 487.777639] Stack: [ 487.777642] ffffffffa00eb5fa ffff8808696d7b60 ffff88086b87d800 0000000000000000 [ 487.777644] ffff8808696d7ac8 ffffffffa01694b6 ffff8808696d7ae8 ffffffff8109c8d5 [ 487.777647] ffff880469158740 ffff880463a27000 ffff88086b87d800 ffff88086b87d800 [ 487.777647] Call Trace: [ 487.777674] [<ffffffffa00eb5fa>] ? drm_gem_object_lookup+0x1a/0xa0 [drm] [ 487.777681] [<ffffffffa01694b6>] mga_crtc_cursor_set+0xc6/0xb60 [mgag200] [ 487.777691] [<ffffffff8109c8d5>] ? find_busiest_group+0x35/0x4a0 [ 487.777696] [<ffffffff81086294>] ? __might_sleep+0x44/0x80 [ 487.777699] [<ffffffff815888c2>] ? __ww_mutex_lock+0x22/0x9c [ 487.777722] [<ffffffffa0104f64>] ? drm_modeset_lock+0x34/0xf0 [drm] [ 487.777733] [<ffffffffa0148d9e>] restore_fbdev_mode+0xee/0x2a0 [drm_kms_helper] [ 487.777742] [<ffffffffa014afce>] drm_fb_helper_restore_fbdev_mode_unlocked+0x2e/0x70 [drm_kms_helper] [ 487.777748] [<ffffffffa014b037>] drm_fb_helper_set_par+0x27/0x50 [drm_kms_helper] [ 487.777752] [<ffffffff8134560c>] fb_set_var+0x18c/0x3f0 [ 487.777777] [<ffffffffa02a9b0a>] ? __ext4_handle_dirty_metadata+0x8a/0x210 [ext4] [ 487.777783] [<ffffffff8133cb97>] fbcon_blank+0x1b7/0x2b0 [ 487.777790] [<ffffffff813be2a3>] do_unblank_screen+0xb3/0x1c0 [ 487.777795] [<ffffffff813b5aba>] vt_ioctl+0x118a/0x1210 [ 487.777801] [<ffffffff813a8fe0>] tty_ioctl+0x3f0/0xc90 [ 487.777808] [<ffffffff81172018>] ? kzfree+0x28/0x30 [ 487.777813] [<ffffffff811e053f>] ? mntput+0x1f/0x30 [ 487.777817] [<ffffffff811d3f5d>] do_vfs_ioctl+0x30d/0x570 [ 487.777822] [<ffffffff8107ed3a>] ? task_work_run+0x8a/0xa0 [ 487.777825] [<ffffffff811d4234>] SyS_ioctl+0x74/0x80 [ 487.777829] [<ffffffff8158aeae>] entry_SYSCALL_64_fastpath+0x12/0x71 [ 487.777851] Code: 65 ff 0d ce 02 a8 7e 5d c3 ba 01 00 00 00 f0 0f b1 17 85 c0 75 e8 b0 01 5d c3 0f 1f 00 65 ff 05 b1 02 a8 7e 31 c0 ba 01 00 00 00 <f0> 0f b1 17 85 c0 75 01 c3 55 89 c6 48 89 e5 e8 4e f5 b1 ff 5d [ 487.777854] RIP [<ffffffff8158aaee>] _raw_spin_lock+0xe/0x30 [ 487.777855] RSP <ffff8808696d79c0> [ 487.777856] CR2: 0000000000000060 [ 487.777860] ---[ end trace 672a2cd555e0ebd3 ]--- The cursor code may be entered with file_priv == NULL && handle == NULL. The problem was introduced by: "bf89209 drm/mga200g: Hold a proper reference for cursor_set" which calls drm_gem_object_lookup(dev, file_priv...). Previously this wasn't a problem because we checked the handle. Move the check early in the function can fix the problem. Signed-off-by: Rui Wang <rui.y.wang@intel.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Dave Airlie <airlied@redhat.com>

OMAP CPU hotplug uses cpu1's clocks and power domains for CPU1 wake up from low power states (or turn on CPU1). This part of code is also part of system suspend (disable_nonboot_cpus()). >From other side, cpu1's clocks and power domains are used by CPUIdle. All above functionality is mutually exclusive and, therefore, lockless clkdm/pwrdm api can be used in omap4_boot_secondary(). This fixes below back-trace on -RT which is triggered by pwrdm_lock/unlock(): BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:917 in_atomic(): 1, irqs_disabled(): 0, pid: 118, name: sh 9 locks held by sh/118: #0: (sb_writers#4){.+.+.+}, at: [<c0144a6c>] vfs_write+0x13c/0x164 #1: (&of->mutex){+.+.+.}, at: [<c01b4c70>] kernfs_fop_write+0x48/0x19c #2: (s_active#24){.+.+.+}, at: [<c01b4c78>] kernfs_fop_write+0x50/0x19c #3: (device_hotplug_lock){+.+.+.}, at: [<c03cbff0>] lock_device_hotplug_sysfs+0xc/0x4c #4: (&dev->mutex){......}, at: [<c03cd284>] device_online+0x14/0x88 #5: (cpu_add_remove_lock){+.+.+.}, at: [<c003af90>] cpu_up+0x50/0x1a0 #6: (cpu_hotplug.lock){++++++}, at: [<c003ae48>] cpu_hotplug_begin+0x0/0xc4 #7: (cpu_hotplug.lock#2){+.+.+.}, at: [<c003aec0>] cpu_hotplug_begin+0x78/0xc4 #8: (boot_lock){+.+...}, at: [<c002b254>] omap4_boot_secondary+0x1c/0x178 Preemption disabled at:[< (null)>] (null) CPU: 0 PID: 118 Comm: sh Not tainted 4.1.12-rt11-01998-gb4a62c3-dirty #137 Hardware name: Generic DRA74X (Flattened Device Tree) [<c0017574>] (unwind_backtrace) from [<c0013be8>] (show_stack+0x10/0x14) [<c0013be8>] (show_stack) from [<c05a8670>] (dump_stack+0x80/0x94) [<c05a8670>] (dump_stack) from [<c05ad158>] (rt_spin_lock+0x24/0x54) [<c05ad158>] (rt_spin_lock) from [<c0030dac>] (clkdm_wakeup+0x10/0x2c) [<c0030dac>] (clkdm_wakeup) from [<c002b2c0>] (omap4_boot_secondary+0x88/0x178) [<c002b2c0>] (omap4_boot_secondary) from [<c0015d00>] (__cpu_up+0xc4/0x164) [<c0015d00>] (__cpu_up) from [<c003b09c>] (cpu_up+0x15c/0x1a0) [<c003b09c>] (cpu_up) from [<c03cd2d4>] (device_online+0x64/0x88) [<c03cd2d4>] (device_online) from [<c03cd360>] (online_store+0x68/0x74) [<c03cd360>] (online_store) from [<c01b4ce0>] (kernfs_fop_write+0xb8/0x19c) [<c01b4ce0>] (kernfs_fop_write) from [<c0144124>] (__vfs_write+0x20/0xd8) [<c0144124>] (__vfs_write) from [<c01449c0>] (vfs_write+0x90/0x164) [<c01449c0>] (vfs_write) from [<c01451e4>] (SyS_write+0x44/0x9c) [<c01451e4>] (SyS_write) from [<c0010240>] (ret_fast_syscall+0x0/0x54) CPU1: smp_ops.cpu_die() returned, trying to resuscitate Cc: Tero Kristo <t-kristo@ti.com> Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com> Signed-off-by: Tony Lindgren <tony@atomide.com>

When a43eec3 ("bpf: introduce bpf_perf_event_output() helper") added PERF_COUNT_SW_BPF_OUTPUT we ended up with a new entry in the event_symbols_sw array that wasn't initialized, thus set to NULL, fix print_symbol_events() to check for that case so that we don't crash if this happens again. (gdb) bt #0 __match_glob (ignore_space=false, pat=<optimized out>, str=<optimized out>) at util/string.c:198 #1 strglobmatch (str=<optimized out>, pat=pat@entry=0x7fffffffe61d "stall") at util/string.c:252 #2 0x00000000004993a5 in print_symbol_events (type=1, syms=0x872880 <event_symbols_sw+160>, max=11, name_only=false, event_glob=0x7fffffffe61d "stall") at util/parse-events.c:1615 #3 print_events (event_glob=event_glob@entry=0x7fffffffe61d "stall", name_only=false) at util/parse-events.c:1675 #4 0x000000000042c79e in cmd_list (argc=1, argv=0x7fffffffe390, prefix=<optimized out>) at builtin-list.c:68 #5 0x00000000004788a5 in run_builtin (p=p@entry=0x871758 <commands+120>, argc=argc@entry=2, argv=argv@entry=0x7fffffffe390) at perf.c:370 #6 0x0000000000420ab0 in handle_internal_command (argv=0x7fffffffe390, argc=2) at perf.c:429 #7 run_argv (argv=0x7fffffffe110, argcp=0x7fffffffe11c) at perf.c:473 #8 main (argc=2, argv=0x7fffffffe390) at perf.c:588 (gdb) p event_symbols_sw[PERF_COUNT_SW_BPF_OUTPUT] $4 = {symbol = 0x0, alias = 0x0} (gdb) A patch to robustify perf to not segfault when the next counter gets added in the kernel will follow this one. Reported-by: Ingo Molnar <mingo@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: David Ahern <dsahern@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/n/tip-57wysblcjfrseb0zg5u7ek10@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Fixes segmentation fault using, for instance: (gdb) run record -I -e intel_pt/tsc=1,noretcomp=1/u /bin/ls Starting program: /home/acme/bin/perf record -I -e intel_pt/tsc=1,noretcomp=1/u /bin/ls Missing separate debuginfos, use: dnf debuginfo-install glibc-2.22-7.fc23.x86_64 [Thread debugging using libthread_db enabled] Using host libthread_db library "/lib64/libthread_db.so.1". Program received signal SIGSEGV, Segmentation fault. 0 x00000000004b9ea5 in tracepoint_error (e=0x0, err=13, sys=0x19b1370 "sched", name=0x19a5d00 "sched_switch") at util/parse-events.c:410 (gdb) bt #0 0x00000000004b9ea5 in tracepoint_error (e=0x0, err=13, sys=0x19b1370 "sched", name=0x19a5d00 "sched_switch") at util/parse-events.c:410 #1 0x00000000004b9fc5 in add_tracepoint (list=0x19a5d20, idx=0x7fffffffb8c0, sys_name=0x19b1370 "sched", evt_name=0x19a5d00 "sched_switch", err=0x0, head_config=0x0) at util/parse-events.c:433 #2 0x00000000004ba334 in add_tracepoint_event (list=0x19a5d20, idx=0x7fffffffb8c0, sys_name=0x19b1370 "sched", evt_name=0x19a5d00 "sched_switch", err=0x0, head_config=0x0) at util/parse-events.c:498 #3 0x00000000004bb699 in parse_events_add_tracepoint (list=0x19a5d20, idx=0x7fffffffb8c0, sys=0x19b1370 "sched", event=0x19a5d00 "sched_switch", err=0x0, head_config=0x0) at util/parse-events.c:936 #4 0x00000000004f6eda in parse_events_parse (_data=0x7fffffffb8b0, scanner=0x19a49d0) at util/parse-events.y:391 #5 0x00000000004bc8e5 in parse_events__scanner (str=0x663ff2 "sched:sched_switch", data=0x7fffffffb8b0, start_token=258) at util/parse-events.c:1361 #6 0x00000000004bca57 in parse_events (evlist=0x19a5220, str=0x663ff2 "sched:sched_switch", err=0x0) at util/parse-events.c:1401 #7 0x0000000000518d5f in perf_evlist__can_select_event (evlist=0x19a3b90, str=0x663ff2 "sched:sched_switch") at util/record.c:253 #8 0x0000000000553c42 in intel_pt_track_switches (evlist=0x19a3b90) at arch/x86/util/intel-pt.c:364 #9 0x00000000005549d1 in intel_pt_recording_options (itr=0x19a2c40, evlist=0x19a3b90, opts=0x8edf68 <record+232>) at arch/x86/util/intel-pt.c:664 #10 0x000000000051e076 in auxtrace_record__options (itr=0x19a2c40, evlist=0x19a3b90, opts=0x8edf68 <record+232>) at util/auxtrace.c:539 #11 0x0000000000433368 in cmd_record (argc=1, argv=0x7fffffffde60, prefix=0x0) at builtin-record.c:1264 #12 0x000000000049bec2 in run_builtin (p=0x8fa2a8 <commands+168>, argc=5, argv=0x7fffffffde60) at perf.c:390 #13 0x000000000049c12a in handle_internal_command (argc=5, argv=0x7fffffffde60) at perf.c:451 #14 0x000000000049c278 in run_argv (argcp=0x7fffffffdcbc, argv=0x7fffffffdcb0) at perf.c:495 #15 0x000000000049c60a in main (argc=5, argv=0x7fffffffde60) at perf.c:618 (gdb) Intel PT attempts to find the sched:sched_switch tracepoint but that seg faults if tracefs is not readable, because the error reporting structure is null, as errors are not reported when automatically adding tracepoints. Fix by checking before using. Committer note: This doesn't take place in a kernel that supports perf_event_attr.context_switch, that is the default way that will be used for tracking context switches, only in older kernels, like 4.2, in a machine with Intel PT (e.g. Broadwell) for non-priviledged users. Further info from a similar patch by Wang: The error is in tracepoint_error: it assumes the 'e' parameter is valid. However, there are many situation a parse_event() can be called without parse_events_error. See result of $ grep 'parse_events(.*NULL)' ./tools/perf/ -r' Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Tong Zhang <ztong@vt.edu> Cc: Wang Nan <wangnan0@huawei.com> Cc: stable@vger.kernel.org # v4.4+ Fixes: 1965817 ("perf tools: Enhance parsing events tracepoint error output") Link: http://lkml.kernel.org/r/1453809921-24596-2-git-send-email-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

If we use USB ID pin as wakeup source, and there is a USB block device on this USB OTG (ID) cable, the system will be deadlock after system resume. The root cause for this problem is: the workqueue ci_otg may try to remove hcd before the driver resume has finished, and hcd will disconnect the device on it, then, it will call device_release_driver, and holds the device lock "dev->mutex", but it is never unlocked since it waits workqueue writeback to run to flush the block information, but the workqueue writeback is freezable, it is not thawed before driver resume has finished. When the driver (device: sd 0:0:0:0:) resume goes to dpm_complete, it tries to get its device lock "dev->mutex", but it can't get it forever, then the deadlock occurs. Below call stacks show the situation. So, in order to fix this problem, we need to change workqueue ci_otg as freezable, then the work item in this workqueue will be run after driver's resume, this workqueue will not be blocked forever like above case since the workqueue writeback has been thawed too. Tested at: i.mx6qdl-sabresd and i.mx6sx-sdb. [ 555.178869] kworker/u2:13 D c07de74c 0 826 2 0x00000000 [ 555.185310] Workqueue: ci_otg ci_otg_work [ 555.189353] Backtrace: [ 555.191849] [<c07de4fc>] (__schedule) from [<c07dec6c>] (schedule+0x48/0xa0) [ 555.198912] r10:ee471ba0 r9:00000000 r8:00000000 r7:00000002 r6:ee470000 r5:ee471ba4 [ 555.206867] r4:ee470000 [ 555.209453] [<c07dec24>] (schedule) from [<c07e2fc4>] (schedule_timeout+0x15c/0x1e0) [ 555.217212] r4:7fffffff r3:edc2b000 [ 555.220862] [<c07e2e68>] (schedule_timeout) from [<c07df6c8>] (wait_for_common+0x94/0x144) [ 555.229140] r8:00000000 r7:00000002 r6:ee470000 r5:ee471ba4 r4:7fffffff [ 555.235980] [<c07df634>] (wait_for_common) from [<c07df790>] (wait_for_completion+0x18/0x1c) [ 555.244430] r10:00000001 r9:c0b5563c r8:c0042e48 r7:ef086000 r6:eea4372c r5:ef131b00 [ 555.252383] r4:00000000 [ 555.254970] [<c07df778>] (wait_for_completion) from [<c0043cb8>] (flush_work+0x19c/0x234) [ 555.263177] [<c0043b1c>] (flush_work) from [<c0043fac>] (flush_delayed_work+0x48/0x4c) [ 555.271106] r8:ed5b5000 r7:c0b38a3c r6:eea439cc r5:eea4372c r4:eea4372c [ 555.277958] [<c0043f64>] (flush_delayed_work) from [<c00eae18>] (bdi_unregister+0x84/0xec) [ 555.286236] r4:eea43520 r3:20000153 [ 555.289885] [<c00ead94>] (bdi_unregister) from [<c02c2154>] (blk_cleanup_queue+0x180/0x29c) [ 555.298250] r5:eea43808 r4:eea43400 [ 555.301909] [<c02c1fd4>] (blk_cleanup_queue) from [<c0417914>] (__scsi_remove_device+0x48/0xb8) [ 555.310623] r7:00000000 r6:20000153 r5:ededa950 r4:ededa800 [ 555.316403] [<c04178cc>] (__scsi_remove_device) from [<c0415e90>] (scsi_forget_host+0x64/0x68) [ 555.325028] r5:ededa800 r4:ed5b5000 [ 555.328689] [<c0415e2c>] (scsi_forget_host) from [<c0409828>] (scsi_remove_host+0x78/0x104) [ 555.337054] r5:ed5b5068 r4:ed5b5000 [ 555.340709] [<c04097b0>] (scsi_remove_host) from [<c04cdfcc>] (usb_stor_disconnect+0x50/0xb4) [ 555.349247] r6:ed5b56e4 r5:ed5b5818 r4:ed5b5690 r3:00000008 [ 555.355025] [<c04cdf7c>] (usb_stor_disconnect) from [<c04b3bc8>] (usb_unbind_interface+0x78/0x25c) [ 555.363997] r8:c13919b4 r7:edd3c000 r6:edd3c020 r5:ee551c68 r4:ee551c00 r3:c04cdf7c [ 555.371892] [<c04b3b50>] (usb_unbind_interface) from [<c03dc248>] (__device_release_driver+0x8c/0x118) [ 555.381213] r10:00000001 r9:edd90c00 r8:c13919b4 r7:ee551c68 r6:c0b546e0 r5:c0b5563c [ 555.389167] r4:edd3c020 [ 555.391752] [<c03dc1bc>] (__device_release_driver) from [<c03dc2fc>] (device_release_driver+0x28/0x34) [ 555.401071] r5:edd3c020 r4:edd3c054 [ 555.404721] [<c03dc2d4>] (device_release_driver) from [<c03db304>] (bus_remove_device+0xe0/0x110) [ 555.413607] r5:edd3c020 r4:ef17f04c [ 555.417253] [<c03db224>] (bus_remove_device) from [<c03d8128>] (device_del+0x114/0x21c) [ 555.425270] r6:edd3c028 r5:edd3c020 r4:ee551c00 r3:00000000 [ 555.431045] [<c03d8014>] (device_del) from [<c04b1560>] (usb_disable_device+0xa4/0x1e8) [ 555.439061] r8:edd3c000 r7:eded8000 r6:00000000 r5:00000001 r4:ee551c00 [ 555.445906] [<c04b14bc>] (usb_disable_device) from [<c04a8e54>] (usb_disconnect+0x74/0x224) [ 555.454271] r9:edd90c00 r8:ee551000 r7:ee551c68 r6:ee551c9c r5:ee551c00 r4:00000001 [ 555.462156] [<c04a8de0>] (usb_disconnect) from [<c04a8fb8>] (usb_disconnect+0x1d8/0x224) [ 555.470259] r10:00000001 r9:edd90000 r8:ee471e2c r7:ee551468 r6:ee55149c r5:ee551400 [ 555.478213] r4:00000001 [ 555.480797] [<c04a8de0>] (usb_disconnect) from [<c04ae5ec>] (usb_remove_hcd+0xa0/0x1ac) [ 555.488813] r10:00000001 r9:ee471eb0 r8:00000000 r7:ef3d9500 r6:eded810c r5:eded80b0 [ 555.496765] r4:eded8000 [ 555.499351] [<c04ae54c>] (usb_remove_hcd) from [<c04d4158>] (host_stop+0x28/0x64) [ 555.506847] r6:eeb50010 r5:eded8000 r4:eeb51010 [ 555.511563] [<c04d4130>] (host_stop) from [<c04d09b8>] (ci_otg_work+0xc4/0x124) [ 555.518885] r6:00000001 r5:eeb50010 r4:eeb502a0 r3:c04d4130 [ 555.524665] [<c04d08f4>] (ci_otg_work) from [<c00454f0>] (process_one_work+0x194/0x420) [ 555.532682] r6:ef086000 r5:eeb502a0 r4:edc44480 [ 555.537393] [<c004535c>] (process_one_work) from [<c00457b0>] (worker_thread+0x34/0x514) [ 555.545496] r10:edc44480 r9:ef086000 r8:c0b1a100 r7:ef086034 r6:00000088 r5:edc44498 [ 555.553450] r4:ef086000 [ 555.556032] [<c004577c>] (worker_thread) from [<c004bab4>] (kthread+0xdc/0xf8) [ 555.563268] r10:00000000 r9:00000000 r8:00000000 r7:c004577c r6:edc44480 r5:eddc15c0 [ 555.571221] r4:00000000 [ 555.573804] [<c004b9d8>] (kthread) from [<c000fef0>] (ret_from_fork+0x14/0x24) [ 555.581040] r7:00000000 r6:00000000 r5:c004b9d8 r4:eddc15c0 [ 553.429383] sh D c07de74c 0 694 691 0x00000000 [ 553.435801] Backtrace: [ 553.438295] [<c07de4fc>] (__schedule) from [<c07dec6c>] (schedule+0x48/0xa0) [ 553.445358] r10:edd3c054 r9:edd3c078 r8:edddbd50 r7:edcbbc00 r6:c1377c34 r5:60000153 [ 553.453313] r4:eddda000 [ 553.455896] [<c07dec24>] (schedule) from [<c07deff8>] (schedule_preempt_disabled+0x10/0x14) [ 553.464261] r4:edd3c058 r3:0000000a [ 553.467910] [<c07defe8>] (schedule_preempt_disabled) from [<c07e0bbc>] (mutex_lock_nested+0x1a0/0x3e8) [ 553.477254] [<c07e0a1c>] (mutex_lock_nested) from [<c03e927c>] (dpm_complete+0xc0/0x1b0) [ 553.485358] r10:00561408 r9:edd3c054 r8:c0b4863c r7:edddbd90 r6:c0b485d8 r5:edd3c020 [ 553.493313] r4:edd3c0d0 [ 553.495896] [<c03e91bc>] (dpm_complete) from [<c03e9388>] (dpm_resume_end+0x1c/0x20) [ 553.503652] r9:00000000 r8:c0b1a9d0 r7:c1334ec0 r6:c1334edc r5:00000003 r4:00000010 [ 553.511544] [<c03e936c>] (dpm_resume_end) from [<c0079894>] (suspend_devices_and_enter+0x158/0x504) [ 553.520604] r4:00000000 r3:c1334efc [ 553.524250] [<c007973c>] (suspend_devices_and_enter) from [<c0079e74>] (pm_suspend+0x234/0x2cc) [ 553.532961] r10:00561408 r9:ed6b7300 r8:00000004 r7:c1334eec r6:00000000 r5:c1334ee8 [ 553.540914] r4:00000003 [ 553.543493] [<c0079c40>] (pm_suspend) from [<c0078a6c>] (state_store+0x6c/0xc0) [ 555.703684] 7 locks held by kworker/u2:13/826: [ 555.708140] #0: ("%s""ci_otg"){++++.+}, at: [<c0045484>] process_one_work+0x128/0x420 [ 555.716277] #1: ((&ci->work)){+.+.+.}, at: [<c0045484>] process_one_work+0x128/0x420 [ 555.724317] #2: (usb_bus_list_lock){+.+.+.}, at: [<c04ae5e4>] usb_remove_hcd+0x98/0x1ac [ 555.732626] #3: (&dev->mutex){......}, at: [<c04a8e28>] usb_disconnect+0x48/0x224 [ 555.740403] #4: (&dev->mutex){......}, at: [<c04a8e28>] usb_disconnect+0x48/0x224 [ 555.748179] #5: (&dev->mutex){......}, at: [<c03dc2f4>] device_release_driver+0x20/0x34 [ 555.756487] #6: (&shost->scan_mutex){+.+.+.}, at: [<c04097d0>] scsi_remove_host+0x20/0x104 Cc: <stable@vger.kernel.org> #v3.14+ Cc: Jun Li <jun.li@nxp.com> Signed-off-by: Peter Chen <peter.chen@nxp.com>

If the lower or upper directory of an overlayfs mount belong to a btrfs file system and we fsync the file through the overlayfs' merged directory we ended up accessing an inode that didn't belong to btrfs as if it were a btrfs inode at btrfs_sync_file() resulting in a crash like the following: [ 7782.588845] BUG: unable to handle kernel NULL pointer dereference at 0000000000000544 [ 7782.590624] IP: [<ffffffffa030b7ab>] btrfs_sync_file+0x11b/0x3e9 [btrfs] [ 7782.591931] PGD 4d954067 PUD 1e878067 PMD 0 [ 7782.592016] Oops: 0002 [#6] PREEMPT SMP DEBUG_PAGEALLOC [ 7782.592016] Modules linked in: btrfs overlay ppdev crc32c_generic evdev xor raid6_pq psmouse pcspkr sg serio_raw acpi_cpufreq parport_pc parport tpm_tis i2c_piix4 tpm i2c_core processor button loop autofs4 ext4 crc16 mbcache jbd2 sr_mod cdrom sd_mod ata_generic virtio_scsi ata_piix virtio_pci libata virtio_ring virtio scsi_mod e1000 floppy [last unloaded: btrfs] [ 7782.592016] CPU: 10 PID: 16437 Comm: xfs_io Tainted: G D 4.5.0-rc6-btrfs-next-26+ #1 [ 7782.592016] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS by qemu-project.org 04/01/2014 [ 7782.592016] task: ffff88001b8d40c0 ti: ffff880137488000 task.ti: ffff880137488000 [ 7782.592016] RIP: 0010:[<ffffffffa030b7ab>] [<ffffffffa030b7ab>] btrfs_sync_file+0x11b/0x3e9 [btrfs] [ 7782.592016] RSP: 0018:ffff88013748be40 EFLAGS: 00010286 [ 7782.592016] RAX: 0000000080000000 RBX: ffff880133b30c88 RCX: 0000000000000001 [ 7782.592016] RDX: 0000000000000001 RSI: ffffffff8148fec0 RDI: 00000000ffffffff [ 7782.592016] RBP: ffff88013748bec0 R08: 0000000000000001 R09: 0000000000000000 [ 7782.624248] R10: ffff88013748be40 R11: 0000000000000246 R12: 0000000000000000 [ 7782.624248] R13: 0000000000000000 R14: 00000000009305a0 R15: ffff880015e3be40 [ 7782.624248] FS: 00007fa83b9cb700(0000) GS:ffff88023ed40000(0000) knlGS:0000000000000000 [ 7782.624248] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 7782.624248] CR2: 0000000000000544 CR3: 00000001fa652000 CR4: 00000000000006e0 [ 7782.624248] Stack: [ 7782.624248] ffffffff8108b5cc ffff88013748bec0 0000000000000246 ffff8800b005ded0 [ 7782.624248] ffff880133b30d60 8000000000000000 7fffffffffffffff 0000000000000246 [ 7782.624248] 0000000000000246 ffffffff81074f9b ffffffff8104357c ffff880015e3be40 [ 7782.624248] Call Trace: [ 7782.624248] [<ffffffff8108b5cc>] ? arch_local_irq_save+0x9/0xc [ 7782.624248] [<ffffffff81074f9b>] ? ___might_sleep+0xce/0x217 [ 7782.624248] [<ffffffff8104357c>] ? __do_page_fault+0x3c0/0x43a [ 7782.624248] [<ffffffff811a2351>] vfs_fsync_range+0x8c/0x9e [ 7782.624248] [<ffffffff811a237f>] vfs_fsync+0x1c/0x1e [ 7782.624248] [<ffffffff811a24d6>] do_fsync+0x31/0x4a [ 7782.624248] [<ffffffff811a2700>] SyS_fsync+0x10/0x14 [ 7782.624248] [<ffffffff81493617>] entry_SYSCALL_64_fastpath+0x12/0x6b [ 7782.624248] Code: 85 c0 0f 85 e2 02 00 00 48 8b 45 b0 31 f6 4c 29 e8 48 ff c0 48 89 45 a8 48 8d 83 d8 00 00 00 48 89 c7 48 89 45 a0 e8 fc 43 18 e1 <f0> 41 ff 84 24 44 05 00 00 48 8b 83 58 ff ff ff 48 c1 e8 07 83 [ 7782.624248] RIP [<ffffffffa030b7ab>] btrfs_sync_file+0x11b/0x3e9 [btrfs] [ 7782.624248] RSP <ffff88013748be40> [ 7782.624248] CR2: 0000000000000544 [ 7782.661994] ---[ end trace 721e14960eb939bc ]--- This started happening since commit 4bacc9c (overlayfs: Make f_path always point to the overlay and f_inode to the underlay) and even though after this change we could still access the btrfs inode through struct file->f_mapping->host or struct file->f_inode, we would end up resulting in more similar issues later on at check_parent_dirs_for_sync() because the dentry we got (from struct file->f_path.dentry) was from overlayfs and not from btrfs, that is, we had no way of getting the dentry that belonged to btrfs (we always got the dentry that belonged to overlayfs). The new patch from Miklos Szeredi, titled "vfs: add file_dentry()" and recently submitted to linux-fsdevel, adds a file_dentry() API that allows us to get the btrfs dentry from the input file and therefore being able to fsync when the upper and lower directories belong to btrfs filesystems. This issue has been reported several times by users in the mailing list and bugzilla. A test case for xfstests is being submitted as well. Fixes: 4bacc9c ("overlayfs: Make f_path always point to the overlay and f_inode to the underlay") Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=101951 Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=109791 Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com> Cc: stable@vger.kernel.org

commit e2c8b87 moved modeset locking inside resume/suspend functions, but missed a code path only executed on lid close/open on older hardware. The result was a deadlock when closing and opening the lid without suspending on such hardware: ============================================= [ INFO: possible recursive locking detected ] 4.6.0-rc1 #385 Not tainted --------------------------------------------- kworker/0:3/88 is trying to acquire lock: (&dev->mode_config.mutex){+.+.+.}, at: [<ffffffffa063e6a4>] intel_display_resume+0x4a/0x12f [i915] but task is already holding lock: (&dev->mode_config.mutex){+.+.+.}, at: [<ffffffffa02d0d4f>] drm_modeset_lock_all+0x3e/0xa6 [drm] other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&dev->mode_config.mutex); lock(&dev->mode_config.mutex); *** DEADLOCK *** May be due to missing lock nesting notation 7 locks held by kworker/0:3/88: #0: ("kacpi_notify"){++++.+}, at: [<ffffffff81068dfc>] process_one_work+0x14a/0x50b #1: ((&dpc->work)#2){+.+.+.}, at: [<ffffffff81068dfc>] process_one_work+0x14a/0x50b #2: ((acpi_lid_notifier).rwsem){++++.+}, at: [<ffffffff8106f874>] __blocking_notifier_call_chain+0x34/0x65 #3: (&dev_priv->modeset_restore_lock){+.+.+.}, at: [<ffffffffa0664cf6>] intel_lid_notify+0x3c/0xd9 [i915] #4: (&dev->mode_config.mutex){+.+.+.}, at: [<ffffffffa02d0d4f>] drm_modeset_lock_all+0x3e/0xa6 [drm] #5: (crtc_ww_class_acquire){+.+.+.}, at: [<ffffffffa02d0d59>] drm_modeset_lock_all+0x48/0xa6 [drm] #6: (crtc_ww_class_mutex){+.+.+.}, at: [<ffffffffa02d0b2a>] modeset_lock+0x13c/0x1cd [drm] stack backtrace: CPU: 0 PID: 88 Comm: kworker/0:3 Not tainted 4.6.0-rc1 #385 Hardware name: LENOVO 2776LEG/2776LEG, BIOS 6EET55WW (3.15 ) 12/19/2011 Workqueue: kacpi_notify acpi_os_execute_deferred 0000000000000000 ffff88022fd5f990 ffffffff8124af06 ffffffff825b39c0 ffffffff825b39c0 ffff88022fd5fa60 ffffffff8108f547 ffff88022fd5fa70 000000008108e817 ffff880230236cc0 0000000000000000 ffffffff825b39c0 Call Trace: [<ffffffff8124af06>] dump_stack+0x67/0x90 [<ffffffff8108f547>] __lock_acquire+0xdb5/0xf71 [<ffffffff8108bd2c>] ? look_up_lock_class+0xbe/0x10a [<ffffffff8108fae2>] lock_acquire+0x137/0x1cb [<ffffffff8108fae2>] ? lock_acquire+0x137/0x1cb [<ffffffffa063e6a4>] ? intel_display_resume+0x4a/0x12f [i915] [<ffffffff8148202f>] mutex_lock_nested+0x7e/0x3a4 [<ffffffffa063e6a4>] ? intel_display_resume+0x4a/0x12f [i915] [<ffffffffa063e6a4>] ? intel_display_resume+0x4a/0x12f [i915] [<ffffffffa02d0b2a>] ? modeset_lock+0x13c/0x1cd [drm] [<ffffffffa063e6a4>] intel_display_resume+0x4a/0x12f [i915] [<ffffffffa063e6a4>] ? intel_display_resume+0x4a/0x12f [i915] [<ffffffffa02d0b2a>] ? modeset_lock+0x13c/0x1cd [drm] [<ffffffffa02d0b2a>] ? modeset_lock+0x13c/0x1cd [drm] [<ffffffffa02d0bf7>] ? drm_modeset_lock+0x17/0x24 [drm] [<ffffffffa02d0c8b>] ? drm_modeset_lock_all_ctx+0x87/0xa1 [drm] [<ffffffffa0664d6a>] intel_lid_notify+0xb0/0xd9 [i915] [<ffffffff8106f4c6>] notifier_call_chain+0x4a/0x6c [<ffffffff8106f88d>] __blocking_notifier_call_chain+0x4d/0x65 [<ffffffff8106f8b9>] blocking_notifier_call_chain+0x14/0x16 [<ffffffffa0011215>] acpi_lid_send_state+0x83/0xad [button] [<ffffffffa00112a6>] acpi_button_notify+0x41/0x132 [button] [<ffffffff812b07df>] acpi_device_notify+0x19/0x1b [<ffffffff812c8570>] acpi_ev_notify_dispatch+0x49/0x64 [<ffffffff812ab9fb>] acpi_os_execute_deferred+0x14/0x20 [<ffffffff81068f17>] process_one_work+0x265/0x50b [<ffffffff810696f5>] worker_thread+0x1fc/0x2dd [<ffffffff810694f9>] ? rescuer_thread+0x309/0x309 [<ffffffff810694f9>] ? rescuer_thread+0x309/0x309 [<ffffffff8106e2d6>] kthread+0xe0/0xe8 [<ffffffff8107bc47>] ? local_clock+0x19/0x22 [<ffffffff81484f42>] ret_from_fork+0x22/0x40 [<ffffffff8106e1f6>] ? kthread_create_on_node+0x1b5/0x1b5 Fixes: e2c8b87 ("drm/i915: Use atomic helpers for suspend, v2.") Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Signed-off-by: Bjørn Mork <bjorn@mork.no> Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1459328913-13719-1-git-send-email-bjorn@mork.no (cherry picked from commit 9f54d4b) Signed-off-by: Jani Nikula <jani.nikula@intel.com>

The bug in a workqueue leads to a stalled IO request in MQ ctx->rq_list with the following backtrace: [ 601.347452] INFO: task kworker/u129:5:1636 blocked for more than 120 seconds. [ 601.347574] Tainted: G O 4.4.5-1-storage+ #6 [ 601.347651] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 601.348142] kworker/u129:5 D ffff880803077988 0 1636 2 0x00000000 [ 601.348519] Workqueue: ibnbd_server_fileio_wq ibnbd_dev_file_submit_io_worker [ibnbd_server] [ 601.348999] ffff880803077988 ffff88080466b900 ffff8808033f9c80 ffff880803078000 [ 601.349662] ffff880807c95000 7fffffffffffffff ffffffff815b0920 ffff880803077ad0 [ 601.350333] ffff8808030779a0 ffffffff815b01d5 0000000000000000 ffff880803077a38 [ 601.350965] Call Trace: [ 601.351203] [<ffffffff815b0920>] ? bit_wait+0x60/0x60 [ 601.351444] [<ffffffff815b01d5>] schedule+0x35/0x80 [ 601.351709] [<ffffffff815b2dd2>] schedule_timeout+0x192/0x230 [ 601.351958] [<ffffffff812d43f7>] ? blk_flush_plug_list+0xc7/0x220 [ 601.352208] [<ffffffff810bd737>] ? ktime_get+0x37/0xa0 [ 601.352446] [<ffffffff815b0920>] ? bit_wait+0x60/0x60 [ 601.352688] [<ffffffff815af784>] io_schedule_timeout+0xa4/0x110 [ 601.352951] [<ffffffff815b3a4e>] ? _raw_spin_unlock_irqrestore+0xe/0x10 [ 601.353196] [<ffffffff815b093b>] bit_wait_io+0x1b/0x70 [ 601.353440] [<ffffffff815b056d>] __wait_on_bit+0x5d/0x90 [ 601.353689] [<ffffffff81127bd0>] wait_on_page_bit+0xc0/0xd0 [ 601.353958] [<ffffffff81096db0>] ? autoremove_wake_function+0x40/0x40 [ 601.354200] [<ffffffff81127cc4>] __filemap_fdatawait_range+0xe4/0x140 [ 601.354441] [<ffffffff81127d34>] filemap_fdatawait_range+0x14/0x30 [ 601.354688] [<ffffffff81129a9f>] filemap_write_and_wait_range+0x3f/0x70 [ 601.354932] [<ffffffff811ced3b>] blkdev_fsync+0x1b/0x50 [ 601.355193] [<ffffffff811c82d9>] vfs_fsync_range+0x49/0xa0 [ 601.355432] [<ffffffff811cf45a>] blkdev_write_iter+0xca/0x100 [ 601.355679] [<ffffffff81197b1a>] __vfs_write+0xaa/0xe0 [ 601.355925] [<ffffffff81198379>] vfs_write+0xa9/0x1a0 [ 601.356164] [<ffffffff811c59d8>] kernel_write+0x38/0x50 The underlying device is a null_blk, with default parameters: queue_mode = MQ submit_queues = 1 Verification that nullb0 has something inflight: root@pserver8:~# cat /sys/block/nullb0/inflight 0 1 root@pserver8:~# find /sys/block/nullb0/mq/0/cpu* -name rq_list -print -exec cat {} \; ... /sys/block/nullb0/mq/0/cpu2/rq_list CTX pending: ffff8838038e2400 ... During debug it became clear that stalled request is always inserted in the rq_list from the following path: save_stack_trace_tsk + 34 blk_mq_insert_requests + 231 blk_mq_flush_plug_list + 281 blk_flush_plug_list + 199 wait_on_page_bit + 192 __filemap_fdatawait_range + 228 filemap_fdatawait_range + 20 filemap_write_and_wait_range + 63 blkdev_fsync + 27 vfs_fsync_range + 73 blkdev_write_iter + 202 __vfs_write + 170 vfs_write + 169 kernel_write + 56 So blk_flush_plug_list() was called with from_schedule == true. If from_schedule is true, that means that finally blk_mq_insert_requests() offloads execution of __blk_mq_run_hw_queue() and uses kblockd workqueue, i.e. it calls kblockd_schedule_delayed_work_on(). That means, that we race with another CPU, which is about to execute __blk_mq_run_hw_queue() work. Further debugging shows the following traces from different CPUs: CPU#0 CPU#1 ---------------------------------- ------------------------------- reqeust A inserted STORE hctx->ctx_map[0] bit marked kblockd_schedule...() returns 1 <schedule to kblockd workqueue> request B inserted STORE hctx->ctx_map[1] bit marked kblockd_schedule...() returns 0 *** WORK PENDING bit is cleared *** flush_busy_ctxs() is executed, but bit 1, set by CPU#1, is not observed As a result request B pended forever. This behaviour can be explained by speculative LOAD of hctx->ctx_map on CPU#0, which is reordered with clear of PENDING bit and executed _before_ actual STORE of bit 1 on CPU#1. The proper fix is an explicit full barrier <mfence>, which guarantees that clear of PENDING bit is to be executed before all possible speculative LOADS or STORES inside actual work function. Signed-off-by: Roman Pen <roman.penyaev@profitbricks.com> Cc: Gioh Kim <gi-oh.kim@profitbricks.com> Cc: Michael Wang <yun.wang@profitbricks.com> Cc: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: linux-block@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: stable@vger.kernel.org Signed-off-by: Tejun Heo <tj@kernel.org>

Assume memory47 is the last online block left in node1. This will hang: # echo offline > /sys/devices/system/node/node1/memory47/state After a couple of minutes, the following pops up in dmesg: INFO: task bash:957 blocked for more than 120 seconds. Not tainted 4.6.0-rc6+ #6 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. bash D ffff8800b7adbaf8 0 957 951 0x00000000 Call Trace: schedule+0x35/0x80 schedule_timeout+0x1ac/0x270 wait_for_completion+0xe1/0x120 kthread_stop+0x4f/0x110 kcompactd_stop+0x26/0x40 __offline_pages.constprop.28+0x7e6/0x840 offline_pages+0x11/0x20 memory_block_action+0x73/0x1d0 memory_subsys_offline+0x47/0x60 device_offline+0x86/0xb0 store_mem_state+0xda/0xf0 dev_attr_store+0x18/0x30 sysfs_kf_write+0x37/0x40 kernfs_fop_write+0x11d/0x170 __vfs_write+0x37/0x120 vfs_write+0xa9/0x1a0 SyS_write+0x55/0xc0 entry_SYSCALL_64_fastpath+0x1a/0xa4 kcompactd is waiting for kcompactd_max_order > 0 when it's woken up to actually exit. Check kthread_should_stop() to break out of the wait. Fixes: 698b1b3 ("mm, compaction: introduce kcompactd"). Reported-by: Reza Arbab <arbab@linux.vnet.ibm.com> Tested-by: Reza Arbab <arbab@linux.vnet.ibm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Rik van Riel <riel@redhat.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: David Rientjes <rientjes@google.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mpt3sas crashes on resume after suspend with WarpDrive flash cards. The reply_post_host_index array is not set back up after the resume, and we deference a stale pointer in _base_interrupt(). [ 47.309711] BUG: unable to handle kernel paging request at ffffc90001f8006c [ 47.318289] IP: [<ffffffffc00863ef>] _base_interrupt+0x49f/0xa30 [mpt3sas] [ 47.326749] PGD 41ccaa067 PUD 41ccab067 PMD 3466c067 PTE 0 [ 47.333848] Oops: 0002 [#1] SMP ... [ 47.452708] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.7.0 #6 [ 47.460506] Hardware name: Dell Inc. OptiPlex 990/06D7TR, BIOS A18 09/24/2013 [ 47.469629] task: ffffffff81c0d500 ti: ffffffff81c00000 task.ti: ffffffff81c00000 [ 47.479112] RIP: 0010:[<ffffffffc00863ef>] [<ffffffffc00863ef>] _base_interrupt+0x49f/0xa30 [mpt3sas] [ 47.490466] RSP: 0018:ffff88041d203e30 EFLAGS: 00010002 [ 47.497801] RAX: 0000000000000001 RBX: ffff880033f4c000 RCX: 0000000000000001 [ 47.506973] RDX: ffffc90001f8006c RSI: 0000000000000082 RDI: 0000000000000082 [ 47.516141] RBP: ffff88041d203eb0 R08: ffff8804118e2820 R09: 0000000000000001 [ 47.525300] R10: 0000000000000001 R11: 00000000100c0000 R12: 0000000000000000 [ 47.534457] R13: ffff880412c487e0 R14: ffff88041a8987d8 R15: 0000000000000001 [ 47.543632] FS: 0000000000000000(0000) GS:ffff88041d200000(0000) knlGS:0000000000000000 [ 47.553796] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 47.561632] CR2: ffffc90001f8006c CR3: 0000000001c06000 CR4: 00000000000406f0 [ 47.570883] Stack: [ 47.575015] 000000001d211228 ffff88041d2100c0 ffff8800c47d8130 0000000000000100 [ 47.584625] ffff8804100c0000 100c000000000000 ffff88041a8992a0 ffff88041a8987f8 [ 47.594230] ffff88041d203e00 ffffffff81111e55 000000000000038c ffff880414ad4280 [ 47.603862] Call Trace: [ 47.608474] <IRQ> [ 47.610413] [<ffffffff81111e55>] ? call_timer_fn+0x35/0x120 [ 47.620539] [<ffffffff81100a1f>] handle_irq_event_percpu+0x7f/0x1c0 [ 47.629061] [<ffffffff81100b8c>] handle_irq_event+0x2c/0x50 [ 47.636859] [<ffffffff81103fff>] handle_edge_irq+0x6f/0x130 [ 47.644654] [<ffffffff8102fbf3>] handle_irq+0x73/0x120 [ 47.652011] [<ffffffff810c6ada>] ? atomic_notifier_call_chain+0x1a/0x20 [ 47.660854] [<ffffffff817e374b>] do_IRQ+0x4b/0xd0 [ 47.667777] [<ffffffff817e160c>] common_interrupt+0x8c/0x8c [ 47.675635] <EOI> Move the reply_post_host_index array setup into mpt3sas_base_map_resources(), which is also in the resume path. Cc: stable@vger.kernel.org Signed-off-by: Greg Edwards <gedwards@fireweed.org> Acked-by: Chaitra P B <chaitra.basappa@broadcom.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

On lubbock board, the probe of the driver crashes by dereferencing very early a platform_data structure which is not set, in pxa2xx_configure_sockets(). The stack fixed is : [ 0.244353] SA1111 Microprocessor Companion Chip: silicon revision 1, metal revision 1 [ 0.256321] sa1111 sa1111: Providing IRQ336-390 [ 0.340899] clocksource: Switched to clocksource oscr0 [ 0.472263] Unable to handle kernel NULL pointer dereference at virtual address 00000004 [ 0.480469] pgd = c0004000 [ 0.483432] [00000004] *pgd=00000000 [ 0.487105] Internal error: Oops: f5 [#1] ARM [ 0.491497] Modules linked in: [ 0.494650] CPU: 0 PID: 1 Comm: swapper Not tainted 4.8.0-rc3-00080-g1aaa68426f0c-dirty #2068 [ 0.503229] Hardware name: Intel DBPXA250 Development Platform (aka Lubbock) [ 0.510344] task: c3e42000 task.stack: c3e44000 [ 0.514984] PC is at pxa2xx_configure_sockets+0x4/0x24 (drivers/pcmcia/pxa2xx_base.c:227) [ 0.520193] LR is at pcmcia_lubbock_init+0x1c/0x38 [ 0.525079] pc : [<c0247c30>] lr : [<c02479b0>] psr: a0000053 [ 0.525079] sp : c3e45e70 ip : 100019ff fp : 00000000 [ 0.536651] r10: c0828900 r9 : c0434838 r8 : 00000000 [ 0.541953] r7 : c0820700 r6 : c0857b30 r5 : c3ec1400 r4 : c0820758 [ 0.548549] r3 : 00000000 r2 : 0000000c r1 : c3c09c40 r0 : c3ec1400 [ 0.555154] Flags: NzCv IRQs on FIQs off Mode SVC_32 ISA ARM Segment none [ 0.562450] Control: 0000397f Table: a0004000 DAC: 00000053 [ 0.568257] Process swapper (pid: 1, stack limit = 0xc3e44190) [ 0.574154] Stack: (0xc3e45e70 to 0xc3e46000) [ 0.578610] 5e60: c4849800 00000000 c3ec1400 c024769c [ 0.586928] 5e80: 00000000 c3ec140c c3c0ee0c c3ec1400 c3ec1434 c020c410 c3ec1400 c3ec1434 [ 0.595244] 5ea0: c0820700 c080b408 c0828900 c020c5f8 00000000 c0820700 c020c578 c020ac5c [ 0.603560] 5ec0: c3e687cc c3e71e10 c0820700 00000000 c3c02de0 c020bae4 c03c62f7 c03c62f7 [ 0.611872] 5ee0: c3e68780 c0820700 c042e034 00000000 c043c440 c020cdec c080b408 00000005 [ 0.620188] 5f00: c042e034 c00096c0 c0034440 c01c730c 20000053 ffffffff 00000000 00000000 [ 0.628502] 5f20: 00000000 c3ffcb87 c3ffcb90 c00346ac c3e66ba0 c03f7914 00000092 00000005 [ 0.636811] 5f40: 00000005 c03f847c 00000091 c03f847c 00000000 00000005 c0434828 00000005 [ 0.645125] 5f60: c043482c 00000092 c043c440 c0828900 c0434838 c0418d2c 00000005 00000005 [ 0.653430] 5f80: 00000000 c041858c 00000000 c032e9f0 00000000 00000000 00000000 00000000 [ 0.661729] 5fa0: 00000000 c032e9f8 00000000 c000f0f0 00000000 00000000 00000000 00000000 [ 0.670020] 5fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 [ 0.678311] 5fe0: 00000000 00000000 00000000 00000000 00000013 00000000 00000000 00000000 [ 0.686673] (pxa2xx_configure_sockets) from pcmcia_lubbock_init (/drivers/pcmcia/sa1111_lubbock.c:161) [ 0.696026] (pcmcia_lubbock_init) from pcmcia_probe (/drivers/pcmcia/sa1111_generic.c:213) [ 0.704358] (pcmcia_probe) from driver_probe_device (/drivers/base/dd.c:378 /drivers/base/dd.c:499) [ 0.712848] (driver_probe_device) from __driver_attach (/./include/linux/device.h:983 /drivers/base/dd.c:733) [ 0.721414] (__driver_attach) from bus_for_each_dev (/drivers/base/bus.c:313) [ 0.729723] (bus_for_each_dev) from bus_add_driver (/drivers/base/bus.c:708) [ 0.738036] (bus_add_driver) from driver_register (/drivers/base/driver.c:169) [ 0.746185] (driver_register) from do_one_initcall (/init/main.c:778) [ 0.754561] (do_one_initcall) from kernel_init_freeable (/init/main.c:843 /init/main.c:851 /init/main.c:869 /init/main.c:1016) [ 0.763409] (kernel_init_freeable) from kernel_init (/init/main.c:944) [ 0.771660] (kernel_init) from ret_from_fork (/arch/arm/kernel/entry-common.S:119) [ 0.779347] Code: c03c6305 c03c631e c03c632e e5903048 (e993000c) All code ======== 0: c03c6305 eorsgt r6, ip, r5, lsl #6 4: c03c631e eorsgt r6, ip, lr, lsl r3 8: c03c632e eorsgt r6, ip, lr, lsr #6 c: e5903048 ldr r3, [r0, #72] ; 0x48 10:* e993000c ldmib r3, {r2, r3} <-- trapping instruction Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

Since commit 4d4c474 ("perf/x86/intel/bts: Fix BTS PMI detection") my box goes boom on boot: | .... node #0, CPUs: #1 #2 #3 #4 #5 #6 #7 | BUG: unable to handle kernel NULL pointer dereference at 0000000000000018 | IP: [<ffffffff8100c463>] intel_bts_interrupt+0x43/0x130 | Call Trace: | <NMI> d [<ffffffff8100b341>] intel_pmu_handle_irq+0x51/0x4b0 | [<ffffffff81004d47>] perf_event_nmi_handler+0x27/0x40 This happens because the code introduced in this commit dereferences the debug store pointer unconditionally. The debug store is not guaranteed to be available, so a NULL pointer check as on other places is required. Fixes: 4d4c474 ("perf/x86/intel/bts: Fix BTS PMI detection") Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Reviewed-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: vince@deater.net Cc: eranian@google.com Link: http://lkml.kernel.org/r/20160920131220.xg5pbdjtznszuyzb@breakpoint.cc Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

try_get_cap_refs can be used as a condition in a wait_event* calls. This is all fine until it has to call __ceph_do_pending_vmtruncate, which in turn acquires the i_truncate_mutex. This leads to a situation in which a task's state is !TASK_RUNNING and at the same time it's trying to acquire a sleeping primitive. In essence a nested sleeping primitives are being used. This causes the following warning: WARNING: CPU: 22 PID: 11064 at kernel/sched/core.c:7631 __might_sleep+0x9f/0xb0() do not call blocking ops when !TASK_RUNNING; state=1 set at [<ffffffff8109447d>] prepare_to_wait_event+0x5d/0x110 ipmi_msghandler tcp_scalable ib_qib dca ib_mad ib_core ib_addr ipv6 CPU: 22 PID: 11064 Comm: fs_checker.pl Tainted: G O 4.4.20-clouder2 #6 Hardware name: Supermicro X10DRi/X10DRi, BIOS 1.1a 10/16/2015 0000000000000000 ffff8838b416fa88 ffffffff812f4409 ffff8838b416fad0 ffffffff81a034f2 ffff8838b416fac0 ffffffff81052b46 ffffffff81a0432c 0000000000000061 0000000000000000 0000000000000000 ffff88167bda54a0 Call Trace: [<ffffffff812f4409>] dump_stack+0x67/0x9e [<ffffffff81052b46>] warn_slowpath_common+0x86/0xc0 [<ffffffff81052bcc>] warn_slowpath_fmt+0x4c/0x50 [<ffffffff8109447d>] ? prepare_to_wait_event+0x5d/0x110 [<ffffffff8109447d>] ? prepare_to_wait_event+0x5d/0x110 [<ffffffff8107767f>] __might_sleep+0x9f/0xb0 [<ffffffff81612d30>] mutex_lock+0x20/0x40 [<ffffffffa04eea14>] __ceph_do_pending_vmtruncate+0x44/0x1a0 [ceph] [<ffffffffa04fa692>] try_get_cap_refs+0xa2/0x320 [ceph] [<ffffffffa04fd6f5>] ceph_get_caps+0x255/0x2b0 [ceph] [<ffffffff81094370>] ? wait_woken+0xb0/0xb0 [<ffffffffa04f2c11>] ceph_write_iter+0x2b1/0xde0 [ceph] [<ffffffff81613f22>] ? schedule_timeout+0x202/0x260 [<ffffffff8117f01a>] ? kmem_cache_free+0x1ea/0x200 [<ffffffff811b46ce>] ? iput+0x9e/0x230 [<ffffffff81077632>] ? __might_sleep+0x52/0xb0 [<ffffffff81156147>] ? __might_fault+0x37/0x40 [<ffffffff8119e123>] ? cp_new_stat+0x153/0x170 [<ffffffff81198cfa>] __vfs_write+0xaa/0xe0 [<ffffffff81199369>] vfs_write+0xa9/0x190 [<ffffffff811b6d01>] ? set_close_on_exec+0x31/0x70 [<ffffffff8119a056>] SyS_write+0x46/0xa0 This happens since wait_event_interruptible can interfere with the mutex locking code, since they both fiddle with the task state. Fix the issue by using the newly-added nested blocking infrastructure in 61ada52 ("sched/wait: Provide infrastructure to deal with nested blocking") Link: https://lwn.net/Articles/628628/ Signed-off-by: Nikolay Borisov <kernel@kyup.com> Signed-off-by: Yan, Zheng <zyan@redhat.com>

Function ib_create_qp() was failing to return an error when rdma_rw_init_mrs() fails, causing a crash further down in ib_create_qp() when trying to dereferece the qp pointer which was actually a negative errno. The crash: crash> log|grep BUG [ 136.458121] BUG: unable to handle kernel NULL pointer dereference at 0000000000000098 crash> bt PID: 3736 TASK: ffff8808543215c0 CPU: 2 COMMAND: "kworker/u64:2" #0 [ffff88084d323340] machine_kexec at ffffffff8105fbb0 #1 [ffff88084d3233b0] __crash_kexec at ffffffff81116758 #2 [ffff88084d323480] crash_kexec at ffffffff8111682d #3 [ffff88084d3234b0] oops_end at ffffffff81032bd6 #4 [ffff88084d3234e0] no_context at ffffffff8106e431 #5 [ffff88084d323530] __bad_area_nosemaphore at ffffffff8106e610 #6 [ffff88084d323590] bad_area_nosemaphore at ffffffff8106e6f4 #7 [ffff88084d3235a0] __do_page_fault at ffffffff8106ebdc #8 [ffff88084d323620] do_page_fault at ffffffff8106f057 #9 [ffff88084d323660] page_fault at ffffffff816e3148 [exception RIP: ib_create_qp+427] RIP: ffffffffa02554fb RSP: ffff88084d323718 RFLAGS: 00010246 RAX: 0000000000000004 RBX: fffffffffffffff4 RCX: 000000018020001f RDX: ffff880830997fc0 RSI: 0000000000000001 RDI: ffff88085f407200 RBP: ffff88084d323778 R8: 0000000000000001 R9: ffffea0020bae210 R10: ffffea0020bae218 R11: 0000000000000001 R12: ffff88084d3237c8 R13: 00000000fffffff4 R14: ffff880859fa5000 R15: ffff88082eb89800 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 #10 [ffff88084d323780] rdma_create_qp at ffffffffa0782681 [rdma_cm] #11 [ffff88084d3237b0] nvmet_rdma_create_queue_ib at ffffffffa07c43f3 [nvmet_rdma] #12 [ffff88084d323860] nvmet_rdma_alloc_queue at ffffffffa07c5ba9 [nvmet_rdma] #13 [ffff88084d323900] nvmet_rdma_queue_connect at ffffffffa07c5c96 [nvmet_rdma] #14 [ffff88084d323980] nvmet_rdma_cm_handler at ffffffffa07c6450 [nvmet_rdma] #15 [ffff88084d3239b0] iw_conn_req_handler at ffffffffa0787480 [rdma_cm] #16 [ffff88084d323a60] cm_conn_req_handler at ffffffffa0775f06 [iw_cm] #17 [ffff88084d323ab0] process_event at ffffffffa0776019 [iw_cm] #18 [ffff88084d323af0] cm_work_handler at ffffffffa0776170 [iw_cm] #19 [ffff88084d323cb0] process_one_work at ffffffff810a1483 #20 [ffff88084d323d90] worker_thread at ffffffff810a211d #21 [ffff88084d323ec0] kthread at ffffffff810a6c5c #22 [ffff88084d323f50] ret_from_fork at ffffffff816e1ebf Fixes: 632bc3f ("IB/core, RDMA RW API: Do not exceed QP SGE send limit") Signed-off-by: Steve Wise <swise@opengridcomputing.com> Cc: stable@vger.kernel.org Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com> Signed-off-by: Doug Ledford <dledford@redhat.com>

In CONFIG_PREEMPT=n kernel a softlockup was observed while the for loop in exit_sem. Apparently it's possible for the loop to take quite a long time and it doesn't have a scheduling point in it. Since the codes is executing under an rcu read section this may also cause rcu stalls, which in turn block synchronize_rcu operations, which more or less de-stabilises the whole system. Fix this by introducing a cond_resched() at the beginning of the loop. So this patch fixes the following: NMI watchdog: BUG: soft lockup - CPU#10 stuck for 23s! [httpd:18119] CPU: 10 PID: 18119 Comm: httpd Tainted: G O 4.4.20-clouder2 #6 Hardware name: Supermicro X10DRi/X10DRi, BIOS 1.1 04/14/2015 task: ffff88348d695280 ti: ffff881c95550000 task.ti: ffff881c95550000 RIP: 0010:[<ffffffff81614bc7>] [<ffffffff81614bc7>] _raw_spin_lock+0x17/0x30 RSP: 0018:ffff881c95553e40 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffff883161b1eea8 RCX: 000000000000000d RDX: 0000000000000001 RSI: 000000000000000e RDI: ffff883161b1eea4 RBP: ffff881c95553ea0 R08: ffff881c95553e68 R09: ffff883fef376f88 R10: ffff881fffb58c20 R11: ffffea0072556600 R12: ffff883161b1eea0 R13: ffff88348d695280 R14: ffff883dec427000 R15: ffff8831621672a0 FS: 0000000000000000(0000) GS:ffff881fffb40000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f3b3723e020 CR3: 0000000001c0a000 CR4: 00000000001406e0 Call Trace: ? exit_sem+0x7c/0x280 do_exit+0x338/0xb40 do_group_exit+0x43/0xd0 SyS_exit_group+0x14/0x20 entry_SYSCALL_64_fastpath+0x16/0x6e Link: http://lkml.kernel.org/r/1475154992-6363-1-git-send-email-kernel@kyup.com Signed-off-by: Nikolay Borisov <kernel@kyup.com> Cc: Herton R. Krzesinski <herton@redhat.com> Cc: Fabian Frederick <fabf@skynet.be> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

ceph: send client metadata to MDS

69f0df0

Implement version 2 of CEPH_MSG_CLIENT_SESSION syntax, which includes additional client metadata to allow the MDS to report on clients by user-sensible names like hostname. Signed-off-by: John Spray <john.spray@redhat.com>

jcsp force-pushed the wip-9189 branch from a3cf27f to 69f0df0 Compare September 15, 2014 13:11

ukernel force-pushed the testing branch 5 times, most recently from 1315b31 to 5ea9d0f Compare September 18, 2014 01:04

ukernel closed this Sep 18, 2014

ukernel deleted the wip-9189 branch September 18, 2014 02:33

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wip-9189: including client metadata when opening sessions#6

wip-9189: including client metadata when opening sessions#6
jcsp wants to merge 1 commit intotestingfrom
wip-9189

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jcsp commented Sep 15, 2014

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ukernel commented Sep 18, 2014

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