diff options
Diffstat (limited to 'src/runtime/trace.go')
| -rw-r--r-- | src/runtime/trace.go | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/src/runtime/trace.go b/src/runtime/trace.go index 33062daa46..169b650eb4 100644 --- a/src/runtime/trace.go +++ b/src/runtime/trace.go @@ -187,6 +187,9 @@ func StartTrace() error { // paired with an end). stopTheWorldGC("start tracing") + // Prevent sysmon from running any code that could generate events. + lock(&sched.sysmonlock) + // We are in stop-the-world, but syscalls can finish and write to trace concurrently. // Exitsyscall could check trace.enabled long before and then suddenly wake up // and decide to write to trace at a random point in time. @@ -196,6 +199,7 @@ func StartTrace() error { if trace.enabled || trace.shutdown { unlock(&trace.bufLock) + unlock(&sched.sysmonlock) startTheWorldGC() return errorString("tracing is already enabled") } @@ -267,6 +271,8 @@ func StartTrace() error { unlock(&trace.bufLock) + unlock(&sched.sysmonlock) + startTheWorldGC() return nil } @@ -279,10 +285,14 @@ func StopTrace() { stopTheWorldGC("stop tracing") // See the comment in StartTrace. + lock(&sched.sysmonlock) + + // See the comment in StartTrace. lock(&trace.bufLock) if !trace.enabled { unlock(&trace.bufLock) + unlock(&sched.sysmonlock) startTheWorldGC() return } @@ -320,6 +330,8 @@ func StopTrace() { trace.shutdown = true unlock(&trace.bufLock) + unlock(&sched.sysmonlock) + startTheWorldGC() // The world is started but we've set trace.shutdown, so new tracing can't start. |