internal/trace/v2: TestTraceGCStress/AllocFree failures

[gopherbot]

#!watchflakes
default <- pkg == "internal/trace/v2" && test == "TestTraceGCStress/AllocFree"

Issue created automatically to collect these failures.

Example (log):

=== RUN   TestTraceGCStress/AllocFree
    reader_test.go:112: unexpected error while reading the trace: no frequency event found
    trace_test.go:596: found bad trace; dumping to test log...
    trace_test.go:597: dumping trace: invalid event type: 0
--- FAIL: TestTraceGCStress/AllocFree (1.26s)

— watchflakes

[gopherbot]

Found new dashboard test flakes for:

#!watchflakes
default <- pkg == "internal/trace/v2" && test == "TestTraceGCStress/AllocFree"

2024-05-14 21:57 gotip-linux-amd64-longtest go@b86527ec internal/trace/v2.TestTraceGCStress/AllocFree (log)

=== RUN   TestTraceGCStress/AllocFree
    reader_test.go:112: unexpected error while reading the trace: no frequency event found
    trace_test.go:596: found bad trace; dumping to test log...
    trace_test.go:597: dumping trace: invalid event type: 0
--- FAIL: TestTraceGCStress/AllocFree (1.26s)

— watchflakes

[mknyszek]

I know what's going on here -- the goroutine stack alloc/free events are occurring in the middle of tracing an event, due to a stack growth. It's able to throw everything off.

[gopherbot]

Change https://go.dev/cl/587597 mentions this issue: runtime: skip tracing events that would cause reentrancy