diff options
| -rw-r--r-- | src/runtime/cpuprof.go | 6 | ||||
| -rw-r--r-- | src/runtime/os_darwin.go | 3 | ||||
| -rw-r--r-- | src/runtime/profbuf.go | 1 |
3 files changed, 8 insertions, 2 deletions
diff --git a/src/runtime/cpuprof.go b/src/runtime/cpuprof.go index 6ef374eaa4..0d7eeacb39 100644 --- a/src/runtime/cpuprof.go +++ b/src/runtime/cpuprof.go @@ -227,7 +227,11 @@ func runtime_pprof_readProfile() ([]uint64, []unsafe.Pointer, bool) { lock(&cpuprof.lock) log := cpuprof.log unlock(&cpuprof.lock) - data, tags, eof := log.read(profBufBlocking) + readMode := profBufBlocking + if GOOS == "darwin" || GOOS == "ios" { + readMode = profBufNonBlocking // For #61768; on Darwin notes are not async-signal-safe. See sigNoteSetup in os_darwin.go. + } + data, tags, eof := log.read(readMode) if len(data) == 0 && eof { lock(&cpuprof.lock) cpuprof.log = nil diff --git a/src/runtime/os_darwin.go b/src/runtime/os_darwin.go index c4f3bb6a81..105de47a1f 100644 --- a/src/runtime/os_darwin.go +++ b/src/runtime/os_darwin.go @@ -81,7 +81,7 @@ func semawakeup(mp *m) { // The read and write file descriptors used by the sigNote functions. var sigNoteRead, sigNoteWrite int32 -// sigNoteSetup initializes an async-signal-safe note. +// sigNoteSetup initializes a single, there-can-only-be-one, async-signal-safe note. // // The current implementation of notes on Darwin is not async-signal-safe, // because the functions pthread_mutex_lock, pthread_cond_signal, and @@ -93,6 +93,7 @@ var sigNoteRead, sigNoteWrite int32 // not support timed waits but is async-signal-safe. func sigNoteSetup(*note) { if sigNoteRead != 0 || sigNoteWrite != 0 { + // Generalizing this would require avoiding the pipe-fork-closeonexec race, which entangles syscall. throw("duplicate sigNoteSetup") } var errno int32 diff --git a/src/runtime/profbuf.go b/src/runtime/profbuf.go index c579f21488..083b55a922 100644 --- a/src/runtime/profbuf.go +++ b/src/runtime/profbuf.go @@ -491,6 +491,7 @@ Read: // Nothing to read right now. // Return or sleep according to mode. if mode == profBufNonBlocking { + // Necessary on Darwin, notetsleepg below does not work in signal handler, root cause of #61768. return nil, nil, false } if !b.w.cas(bw, bw|profReaderSleeping) { |