libcontainerd/supervisor: fix data race#47300
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cpuguy83 merged 1 commit intomoby:masterfrom Feb 1, 2024
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The monitorDaemon() goroutine calls startContainerd() then blocks on <-daemonWaitCh to wait for it to exit. The startContainerd() function would (re)initialize the daemonWaitCh so a restarted containerd could be waited on. This implementation was race-free because startContainerd() would synchronously initialize the daemonWaitCh before returning. When the call to start the managed containerd process was moved into the waiter goroutine, the code to initialize the daemonWaitCh struct field was also moved into the goroutine. This introduced a race condition. Move the daemonWaitCh initialization to guarantee that it happens before the startContainerd() call returns. Signed-off-by: Cory Snider <csnider@mirantis.com>
dmcgowan
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Feb 1, 2024
cpuguy83
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Feb 1, 2024
This was referenced Feb 3, 2024
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libcontainerd/supervisor.(*remote).monitorDaemon()) #47287- What I did
I fixed a data race in libcontainerd/supervisor that I added in #44215.
- How I did it
The monitorDaemon() goroutine calls startContainerd() then blocks on <-daemonWaitCh to wait for it to exit. The startContainerd() function would (re)initialize the daemonWaitCh so a restarted containerd could be waited on. This implementation was race-free because startContainerd() would synchronously initialize the daemonWaitCh before returning. When the call to start the managed containerd process was moved into the waiter goroutine, the code to initialize the daemonWaitCh struct field was also moved into the goroutine. This introduced a race condition.
Move the daemonWaitCh initialization to guarantee that it happens before the startContainerd() call returns.
- How to verify it
Build a daemon with
BUILDFLAGS=-race. Start it and check that noWARNING: DATA RACEmessages are emitted.Verify that the containerd supervisor is working correctly: it is launched when the daemon starts up, is restarted when killed, and is shut down when the daemon shuts down.
- Description for the changelog
- A picture of a cute animal (not mandatory but encouraged)