Golang internal/trace: TestTraceGCStress/AllocFree failures

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

Issue created automatically to collect these failures.

Example (log):

=== RUN   TestTraceGCStress/AllocFree
    trace_test.go:614: stderr: runtime: out of memory: cannot allocate 4194304-byte block (4209803264 in use)
        fatal error: out of memory

        goroutine 55 gp=0xa489d48 m=11 mp=0x117d4808 [running]:
        runtime.throw({0x8113430, 0xd})
            /home/swarming/.swarming/w/ir/x/w/goroot/src/runtime/panic.go:1094 +0x35 fp=0xbc50f18 sp=0xbc50f04 pc=0x80bc8a5
        runtime.(*mcache).refill(0xf7f62848, 0x59)
            /home/swarming/.swarming/w/ir/x/w/goroot/src/runtime/mcache.go:186 +0x234 fp=0xbc50f44 sp=0xbc50f18 pc=0x8061894
        runtime.(*mcache).nextFree(0xf7f62848, 0x59)
...
            /home/swarming/.swarming/w/ir/x/w/goroot/src/runtime/trace.go:781 +0x54 fp=0xa82bf9c sp=0xa82bf78 pc=0x80c0004
        runtime/trace.(*traceMultiplexer).startLocked.func1()
            /home/swarming/.swarming/w/ir/x/w/goroot/src/runtime/trace/subscribe.go:167 +0xb2 fp=0xa82bff0 sp=0xa82bf9c pc=0x80f1f72
        runtime.goexit({})
            /home/swarming/.swarming/w/ir/x/w/goroot/src/runtime/asm_386.s:1386 +0x1 fp=0xa82bff4 sp=0xa82bff0 pc=0x80c1ba1
        created by runtime/trace.(*traceMultiplexer).startLocked in goroutine 1
            /home/swarming/.swarming/w/ir/x/w/goroot/src/runtime/trace/subscribe.go:157 +0x10d
        exit status 2
    trace_test.go:616: exit status 1
--- FAIL: TestTraceGCStress/AllocFree (3.26s)

— watchflakes

Comment From: gopherbot

Found new dashboard test flakes for:

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

2025-06-06 19:45 go1.25-linux-386-longtest release-branch.go1.25@5abb1d84 internal/trace.TestTraceGCStress/AllocFree (log)

=== RUN TestTraceGCStress/AllocFree trace_test.go:614: stderr: runtime: out of memory: cannot allocate 4194304-byte block (4209803264 in use) fatal error: out of memory goroutine 55 gp=0xa489d48 m=11 mp=0x117d4808 [running]: runtime.throw({0x8113430, 0xd}) /home/swarming/.swarming/w/ir/x/w/goroot/src/runtime/panic.go:1094 +0x35 fp=0xbc50f18 sp=0xbc50f04 pc=0x80bc8a5 runtime.(*mcache).refill(0xf7f62848, 0x59) /home/swarming/.swarming/w/ir/x/w/goroot/src/runtime/mcache.go:186 +0x234 fp=0xbc50f44 sp=0xbc50f18 pc=0x8061894 runtime.(*mcache).nextFree(0xf7f62848, 0x59) ... /home/swarming/.swarming/w/ir/x/w/goroot/src/runtime/trace.go:781 +0x54 fp=0xa82bf9c sp=0xa82bf78 pc=0x80c0004 runtime/trace.(*traceMultiplexer).startLocked.func1() /home/swarming/.swarming/w/ir/x/w/goroot/src/runtime/trace/subscribe.go:167 +0xb2 fp=0xa82bff0 sp=0xa82bf9c pc=0x80f1f72 runtime.goexit({}) /home/swarming/.swarming/w/ir/x/w/goroot/src/runtime/asm_386.s:1386 +0x1 fp=0xa82bff4 sp=0xa82bff0 pc=0x80c1ba1 created by runtime/trace.(*traceMultiplexer).startLocked in goroutine 1 /home/swarming/.swarming/w/ir/x/w/goroot/src/runtime/trace/subscribe.go:157 +0x10d exit status 2 trace_test.go:616: exit status 1 --- FAIL: TestTraceGCStress/AllocFree (3.26s)

2025-06-27 15:23 go1.25-linux-amd64-longtest-noswissmap release-branch.go1.25@fdc076ce internal/trace.TestTraceGCStress/AllocFree (log)

=== RUN TestTraceGCStress/AllocFree reader_test.go:119: unexpected error while reading the trace: inconsistent status for goroutine 1: old Waiting vs. new Running trace_test.go:663: found bad trace; dumping to test log... trace_test.go:674: Trace Go1.25 EventBatch gen=1 m=18446744073709551615 time=81295159521 size=26 Sync Frequency freq=15625000 ClockSnapshot dt=134 mono=5202890217913 sec=1751402864 nsec=286350015 ExperimentalBatch exp=1 gen=1 m=18446744073709551615 time=81295160132 data="\x01\x80\x80\x80\x80\x80\x18\x80@\b\x80\x10" ... String id=120 data="runtime.chanrecv1" String id=121 data="/home/swarming/.swarming/w/ir/x/w/goroot/src/runtime/chan.go" String id=122 data="runtime.(*wakeableSleep).sleep" String id=123 data="runtime.(*scavengerState).park" --- FAIL: TestTraceGCStress/AllocFree (48.52s)

2025-07-07 16:14 gotip-linux-amd64-longtest-noswissmap go@33fb4819 internal/trace.TestTraceGCStress/AllocFree (log)

=== RUN TestTraceGCStress/AllocFree reader_test.go:119: unexpected error while reading the trace: tried to end event GCSweepBegin, but not in-flight trace_test.go:668: found bad trace; dumping to test log... trace_test.go:679: Trace Go1.25 EventBatch gen=1 m=18446744073709551615 time=13060334880 size=25 Sync Frequency freq=15625000 ClockSnapshot dt=135 mono=835861440955 sec=1751905751 nsec=780622697 ExperimentalBatch exp=1 gen=1 m=18446744073709551615 time=13060335530 data="\x01\x80\x80\x80\x80\x80\x18\x80@\b\x80\x10" ... String id=134 data="time.Sleep" String id=135 data="/home/swarming/.swarming/w/ir/x/w/goroot/src/runtime/time.go" String id=136 data="runtime/trace.runtime_readTrace" String id=137 data="runtime.forcegchelper" --- FAIL: TestTraceGCStress/AllocFree (55.85s)

2025-07-08 16:29 go1.25-linux-amd64-longtest-noswissmap release-branch.go1.25@2899144b internal/trace.TestTraceGCStress/AllocFree (log)

=== RUN TestTraceGCStress/AllocFree reader_test.go:119: unexpected error while reading the trace: broken trace: failed to advance: frontier: [gen=1] M 20433 [GoStart time=142262309504 g=45 g_seq=1050] M 20439 [GoStart time=142262331072 g=40 g_seq=823] M 20430 [GoStart time=142262352640 g=46 g_seq=1024] M 20442 [GoStart time=142262389376 g=42 g_seq=631] M 20440 [GoStart time=142262390208 g=49 g_seq=1114] M 20435 [GoStart time=142262415424 g=42 g_seq=632] ... String id=136 data="runtime.traceStartReadCPU" String id=137 data="runtime.updateMaxProcsGoroutine" String id=138 data="runtime.(*scavengerState).park" String id=139 data="runtime.(*scavengerState).sleep" --- FAIL: TestTraceGCStress/AllocFree (43.78s)

2025-07-08 18:30 gotip-linux-amd64-longtest-aliastypeparams go@54c9d776 internal/trace.TestTraceGCStress/AllocFree (log)

=== RUN TestTraceGCStress/AllocFree trace_test.go:648: stderr: SIGSEGV: segmentation violation PC=0x45d4e4 m=0 sigcode=1 addr=0x7b295376a000 goroutine 0 gp=0x590140 m=0 mp=0x590e40 [idle]: runtime.traceAdvance.func6() /home/swarming/.swarming/w/ir/x/w/goroot/src/runtime/trace.go:679 +0xa4 fp=0x7ffed0dc8af8 sp=0x7ffed0dc8ab8 pc=0x45d4e4 runtime.systemstack(0x47921f) /home/swarming/.swarming/w/ir/x/w/goroot/src/runtime/asm_amd64.s:513 +0x4a fp=0x7ffed0dc8b08 sp=0x7ffed0dc8af8 pc=0x474d0a ... r13 0xc00010a028 r14 0x590140 r15 0xc00010a028 rip 0x45d4e4 rflags 0x10206 cs 0x33 fs 0x0 gs 0x0 trace_test.go:650: exit status 2 --- FAIL: TestTraceGCStress/AllocFree (1.53s)

— watchflakes