Details
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Bug
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Status: Resolved (View Workflow)
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Critical
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Resolution: Fixed
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Jenkins 2.238
Description
After launching an agent it keeps hanging with the following text :
[05/06/20 20:34:24] [SSH] Starting agent process: cd "/var/lib/jenkins" && java -jar remoting.jar -workDir /var/lib/jenkins May 06, 2020 8:34:25 PM org.jenkinsci.remoting.engine.WorkDirManager initializeWorkDir INFO: Using /var/lib/jenkins/remoting as a remoting work directory May 06, 2020 8:34:25 PM org.jenkinsci.remoting.engine.WorkDirManager setupLogging INFO: Both error and output logs will be printed to /var/lib/jenkins/remoting <===[JENKINS REMOTING CAPACITY]===>channel started Remoting version: 4.3 This is a Unix agent
This happens since a couple of weeks
jstack reports a deadlock in attachment :
Found one Java-level deadlock:
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"pool-1-thread-4 for channel id=17236":
waiting to lock monitor 0x00007fbd8c015bc8 (object 0x000000076e658428, a hudson.slaves.SlaveComputer$SlaveInitializer$1),
which is held by "Channel reader thread: channel"
"Channel reader thread: channel":
waiting to lock monitor 0x00007fbd9401aed8 (object 0x000000076ded1cc8, a hudson.remoting.RemoteClassLoader),
which is held by "pool-1-thread-4 for channel id=17236"
On april 3 2020 in commit https://github.com/jenkinsci/jenkins/commit/3262d8b7cfbdd1a2e026ad34644e0f9607f5724d
a new synchronized method was added that is partly the cause of this deadlock .See line 1026 in main/java/hudson/slaves/SlaveComputer.java
Attachments
Issue Links
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Activity
The “new” method was just an override of an existing synchronized method, though the deadlock does smell like a regression in the new code before the super call.
You have a custom logger on hudson.remoting.Channel (or hudson.remoting) at FINE or below I think? As a workaround, try removing that logger.
Brian Besl
added a comment - We are still suffering from what appears to be this issue. Both on 2.235.1 and 2.243.
The agent hang is the same as reported. But I don't know how for the java deadlock originally reported.
Brian Besl
added a comment - We are still suffering from what appears to be this issue. Both on 2.235.1 and 2.243.
The agent hang is the same as reported. But I don't know how for the java deadlock originally reported. beslbx better to file a distinct issue and perhaps Link to this one. Unless the deadlock details match those here, you are probably seeing something unrelated.
FYI jglick since your change is mentioned.