trace: fix race condition #279
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trace/trace.go
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| t.lock.RLock() | ||
| } | ||
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| func (t *Trace) runlock() { |
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my eye/brain reads this as "run lock" :(
Found with `go test -race -run=TestPatchConflicts ./test/integration/apiserver`
in Kubernetes.
writeTraceSteps gets called while the mutex of t is locked, so iterating over
t.traceItems is fine. But then it calls stepOrTrace.time = Trace.time of
another instance. Retrieving that time is done without locking the mutex of
that other instance and thus races with setting the end time of that trace in
End.
WARNING: DATA RACE
Write at 0x00c009fed898 by goroutine 124291:
k8s.io/kubernetes/vendor/k8s.io/utils/trace.(*Trace).Log()
/home/prow/go/src/k8s.io/kubernetes/_output/local/go/src/k8s.io/kubernetes/vendor/k8s.io/utils/trace/trace.go:175 +0xc4
k8s.io/kubernetes/vendor/k8s.io/utils/trace.(*Trace).LogIfLong()
/home/prow/go/src/k8s.io/kubernetes/_output/local/go/src/k8s.io/kubernetes/vendor/k8s.io/utils/trace/trace.go:194 +0xc4
k8s.io/kubernetes/vendor/k8s.io/component-base/tracing.(*Span).End()
/home/prow/go/src/k8s.io/kubernetes/_output/local/go/src/k8s.io/kubernetes/vendor/k8s.io/component-base/tracing/tracing.go:67 +0x8f
k8s.io/kubernetes/vendor/k8s.io/apiserver/pkg/storage/etcd3.(*store).GuaranteedUpdate.func2()
/home/prow/go/src/k8s.io/kubernetes/_output/local/go/src/k8s.io/kubernetes/vendor/k8s.io/apiserver/pkg/storage/etcd3/store.go:384 +0x3e
runtime.deferreturn()
/home/prow/go/src/k8s.io/kubernetes/_output/local/.gimme/versions/go1.20.2.linux.amd64/src/runtime/panic.go:476 +0x32
k8s.io/kubernetes/vendor/k8s.io/apiserver/pkg/storage/cacher.(*Cacher).GuaranteedUpdate()
/home/prow/go/src/k8s.io/kubernetes/_output/local/go/src/k8s.io/kubernetes/vendor/k8s.io/apiserver/pkg/storage/cacher/cacher.go:839 +0x1cc
k8s.io/kubernetes/vendor/k8s.io/apiserver/pkg/registry/generic/registry.(*DryRunnableStorage).GuaranteedUpdate()
/home/prow/go/src/k8s.io/kubernetes/_output/local/go/src/k8s.io/kubernetes/vendor/k8s.io/apiserver/pkg/registry/generic/registry/dryrun.go:93 +0x321
k8s.io/kubernetes/vendor/k8s.io/apiserver/pkg/registry/generic/registry.(*Store).Update()
/home/prow/go/src/k8s.io/kubernetes/_output/local/go/src/k8s.io/kubernetes/vendor/k8s.io/apiserver/pkg/registry/generic/registry/store.go:559 +0x858
k8s.io/kubernetes/pkg/registry/core/secret/storage.(*REST).Update()
<autogenerated>:1 +0xfe
k8s.io/kubernetes/vendor/k8s.io/apiserver/pkg/endpoints/handlers.(*patcher).patchResource.func2()
/home/prow/go/src/k8s.io/kubernetes/_output/local/go/src/k8s.io/kubernetes/vendor/k8s.io/apiserver/pkg/endpoints/handlers/patch.go:666 +0x1f1
k8s.io/kubernetes/vendor/k8s.io/apiserver/pkg/endpoints/handlers.(*patcher).patchResource.func3()
/home/prow/go/src/k8s.io/kubernetes/_output/local/go/src/k8s.io/kubernetes/vendor/k8s.io/apiserver/pkg/endpoints/handlers/patch.go:672 +0x57
k8s.io/kubernetes/vendor/k8s.io/apiserver/pkg/endpoints/handlers/finisher.finishRequest.func1()
/home/prow/go/src/k8s.io/kubernetes/_output/local/go/src/k8s.io/kubernetes/vendor/k8s.io/apiserver/pkg/endpoints/handlers/finisher/finisher.go:117 +0xfa
Previous read at 0x00c009fed898 by goroutine 124286:
k8s.io/kubernetes/vendor/k8s.io/utils/trace.(*Trace).time()
/home/prow/go/src/k8s.io/kubernetes/_output/local/go/src/k8s.io/kubernetes/vendor/k8s.io/utils/trace/trace.go:110 +0x3e
k8s.io/kubernetes/vendor/k8s.io/utils/trace.(*Trace).writeTraceSteps()
/home/prow/go/src/k8s.io/kubernetes/_output/local/go/src/k8s.io/kubernetes/vendor/k8s.io/utils/trace/trace.go:235 +0x17a
k8s.io/kubernetes/vendor/k8s.io/utils/trace.(*Trace).logTrace()
/home/prow/go/src/k8s.io/kubernetes/_output/local/go/src/k8s.io/kubernetes/vendor/k8s.io/utils/trace/trace.go:216 +0x4c7
k8s.io/kubernetes/vendor/k8s.io/utils/trace.(*Trace).Log()
/home/prow/go/src/k8s.io/kubernetes/_output/local/go/src/k8s.io/kubernetes/vendor/k8s.io/utils/trace/trace.go:179 +0x118
k8s.io/kubernetes/vendor/k8s.io/utils/trace.(*Trace).LogIfLong()
/home/prow/go/src/k8s.io/kubernetes/_output/local/go/src/k8s.io/kubernetes/vendor/k8s.io/utils/trace/trace.go:194 +0xc4
k8s.io/kubernetes/vendor/k8s.io/component-base/tracing.(*Span).End()
/home/prow/go/src/k8s.io/kubernetes/_output/local/go/src/k8s.io/kubernetes/vendor/k8s.io/component-base/tracing/tracing.go:67 +0x8f
k8s.io/kubernetes/vendor/k8s.io/apiserver/pkg/endpoints/handlers.PatchResource.func1.1()
/home/prow/go/src/k8s.io/kubernetes/_output/local/go/src/k8s.io/kubernetes/vendor/k8s.io/apiserver/pkg/endpoints/handlers/patch.go:69 +0x3e
...
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/approve thanks @pohly |
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[APPROVALNOTIFIER] This PR is APPROVED This pull-request has been approved by: dims, pohly The full list of commands accepted by this bot can be found here. The pull request process is described here
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What type of PR is this?
/kind bug
What this PR does / why we need it:
writeTraceSteps gets called while the mutex of t is locked, so iterating over t.traceItems is fine. But then it calls stepOrTrace.time = Trace.time of another instance. Retrieving that time is done without locking the mutex of that other instance and thus races with setting the end time of that trace in End.
Which issue(s) this PR fixes:
Special notes for your reviewer:
Found with
go test -race -run=TestPatchConflicts ./test/integration/apiserverin Kubernetes.Release note: