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Fix deadlock in dd-task-scheduler #10096

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Merged
rkennke merged 12 commits into from
Dec 11, 2025
Merged

Fix deadlock in dd-task-scheduler #10096

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306201e
[PROF-13025] Fix deadlock in dd-task-scheduler
rkennke Dec 8, 2025
6bdc537
Load class using ClassLoader
rkennke Dec 8, 2025
501bb1b
Merge branch 'master' into PROF-13025
rkennke Dec 9, 2025
68f4a31
Load Handlers class before initializing JMX
rkennke Dec 9, 2025
d9bb39f
Merge remote-tracking branch 'origin/PROF-13025' into PROF-13025
rkennke Dec 9, 2025
3e11771
Merge remote-tracking branch 'origin/master' into PROF-13025
rkennke Dec 9, 2025
46a956d
Use AGENT_CLASSLOADER directly
rkennke Dec 9, 2025
5510b08
Merge branch 'master' into PROF-13025
rkennke Dec 9, 2025
e5ac639
Move load of Handlers into registerSmapEntryEvent()
rkennke Dec 9, 2025
d44266e
Merge branch 'master' into PROF-13025
rkennke Dec 10, 2025
076a11c
Replace internal Jira ref with JBS bug issue
rkennke Dec 10, 2025
99ec036
Merge branch 'master' into PROF-13025
rkennke Dec 10, 2025
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8 changes: 8 additions & 0 deletions ...enjdk/src/main/java/com/datadog/profiling/controller/openjdk/events/SmapEntryFactory.java
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Expand Up @@ -27,6 +27,14 @@ public class SmapEntryFactory {
private static final SmapEntryCache SMAP_ENTRY_CACHE = new SmapEntryCache(Duration.ofMillis(500));

static {
// Load JFR Handlers class early, if present (it has been moved and renamed in JDK23+).
// This prevents a deadlock. See PROF-13025.
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@bric3 bric3 Dec 9, 2025

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suggestion: Is there a JDK bug id as well to drop here ?

The deadlock has been reported to upstream, and a fix has been proposed there

try {
Class.forName("jdk.jfr.events.Handlers");
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@jbachorik jbachorik Dec 8, 2025 •
edited
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We are touching this class only when we have JFR available, so loading the Handlers class should not be disturbing anything.
But - we have smap entry events disabled by default, yet we are getting these issues ... I have a suspicion that we are initing the support regardless of the enablement status. Could you check for PROFILING_SMAP_COLLECTION_ENABLED setting before merging this PR?

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@rkennke rkennke Dec 8, 2025

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This seems to be slighly more complex. The smap event is registered in datadog.trace.bootstrap.Agent and there we probably don't have easy access to PROFILING_SMAP_COLLECTION_ENABLED (not sure), and it might also affect other events. I filed PROF-13213 for a deeper investigation. I would merge this PR as-is. Is that ok?

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@jbachorik jbachorik Dec 8, 2025

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LGTM!

} catch (Exception e) {
// Ignore when the class is not found or anything else goes wrong.
}

if (!JavaVirtualMachine.isJ9() && !JavaVirtualMachine.isOracleJDK8()) {
SMAP_ENTRY_EVENT_TYPE = EventType.getEventType(SmapEntryEvent.class);
AGGREGATED_SMAP_ENTRY_EVENT_TYPE = EventType.getEventType(AggregatedSmapEntryEvent.class);
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