diff options
| -rw-r--r-- | src/runtime/proc.go | 5 | ||||
| -rw-r--r-- | src/runtime/trace.go | 25 |
2 files changed, 21 insertions, 9 deletions
diff --git a/src/runtime/proc.go b/src/runtime/proc.go index 363e8befe6..fd892115bf 100644 --- a/src/runtime/proc.go +++ b/src/runtime/proc.go @@ -1999,7 +1999,6 @@ func oneNewExtraM() { mp.lockedg.set(gp) gp.lockedm.set(mp) gp.goid = sched.goidgen.Add(1) - gp.trace.sysBlockTraced = true if raceenabled { gp.racectx = racegostart(abi.FuncPCABIInternal(newextram) + sys.PCQuantum) } @@ -2705,7 +2704,7 @@ func execute(gp *g, inheritTime bool) { if traceEnabled() { // GoSysExit has to happen when we have a P, but before GoStart. // So we emit it here. - if gp.syscallsp != 0 && gp.trace.sysBlockTraced { + if gp.syscallsp != 0 { traceGoSysExit() } traceGoStart() @@ -3856,7 +3855,6 @@ func reentersyscall(pc, sp uintptr) { } gp.m.syscalltick = gp.m.p.ptr().syscalltick - gp.trace.sysBlockTraced = true pp := gp.m.p.ptr() pp.m = 0 gp.m.oldp.set(pp) @@ -3917,7 +3915,6 @@ func entersyscallblock() { gp.throwsplit = true gp.stackguard0 = stackPreempt // see comment in entersyscall gp.m.syscalltick = gp.m.p.ptr().syscalltick - gp.trace.sysBlockTraced = true gp.m.p.ptr().syscalltick++ // Leave SP around for GC and traceback. diff --git a/src/runtime/trace.go b/src/runtime/trace.go index 9c7792d42b..45a066e7a2 100644 --- a/src/runtime/trace.go +++ b/src/runtime/trace.go @@ -163,10 +163,10 @@ var trace struct { // gTraceState is per-G state for the tracer. type gTraceState struct { - sysExitTicks int64 // cputicks when syscall has returned - sysBlockTraced bool // StartTrace has emitted EvGoInSyscall about this goroutine - seq uint64 // trace event sequencer - lastP puintptr // last P emitted an event for this goroutine + sysExitTicks int64 // cputicks when syscall has returned + tracedSyscallEnter bool // syscall or cgo was entered while trace was enabled or StartTrace has emitted EvGoInSyscall about this goroutine + seq uint64 // trace event sequencer + lastP puintptr // last P emitted an event for this goroutine } // mTraceState is per-M state for the tracer. @@ -309,6 +309,7 @@ func StartTrace() error { } if status == _Gsyscall { gp.trace.seq++ + gp.trace.tracedSyscallEnter = true traceEvent(traceEvGoInSyscall, -1, gp.goid) } else if status == _Gdead && gp.m != nil && gp.m.isextra { // Trigger two trace events for the dead g in the extra m, @@ -320,9 +321,16 @@ func StartTrace() error { id := trace.stackTab.put([]uintptr{logicalStackSentinel, startPCforTrace(0) + sys.PCQuantum}) // no start pc traceEvent(traceEvGoCreate, -1, gp.goid, uint64(id), stackID) gp.trace.seq++ + gp.trace.tracedSyscallEnter = true traceEvent(traceEvGoInSyscall, -1, gp.goid) } else { - gp.trace.sysBlockTraced = false + // We need to explicitly clear the flag. A previous trace might have ended with a goroutine + // not emitting a GoSysExit and clearing the flag, leaving it in a stale state. Clearing + // it here makes it unambiguous to any goroutine exiting a syscall racing with us that + // no EvGoInSyscall event was emitted for it. (It's not racy to set this flag here, because + // it'll only get checked when the goroutine runs again, which will be after the world starts + // again.) + gp.trace.tracedSyscallEnter = false } }) traceProcStart() @@ -1603,11 +1611,18 @@ func traceGoSysCall() { // Skip the extra trampoline frame used on most systems. skip = 4 } + getg().m.curg.trace.tracedSyscallEnter = true traceEvent(traceEvGoSysCall, skip) } func traceGoSysExit() { gp := getg().m.curg + if !gp.trace.tracedSyscallEnter { + // There was no syscall entry traced for us at all, so there's definitely + // no EvGoSysBlock or EvGoInSyscall before us, which EvGoSysExit requires. + return + } + gp.trace.tracedSyscallEnter = false ts := gp.trace.sysExitTicks if ts != 0 && ts < trace.ticksStart { // There is a race between the code that initializes sysExitTicks |