diff options
Diffstat (limited to 'src/runtime/proc.go')
| -rw-r--r-- | src/runtime/proc.go | 33 |
1 files changed, 24 insertions, 9 deletions
diff --git a/src/runtime/proc.go b/src/runtime/proc.go index 263945dd6c..1ec4712a2b 100644 --- a/src/runtime/proc.go +++ b/src/runtime/proc.go @@ -2036,10 +2036,30 @@ func needm(signal bool) { osSetupTLS(mp) // Install g (= m->g0) and set the stack bounds - // to match the current stack. + // to match the current stack. If we don't actually know + // how big the stack is, like we don't know how big any + // scheduling stack is, but we assume there's at least 32 kB. + // If we can get a more accurate stack bound from pthread, + // use that. setg(mp.g0) - sp := getcallersp() - callbackUpdateSystemStack(mp, sp, signal) + gp := getg() + gp.stack.hi = getcallersp() + 1024 + gp.stack.lo = getcallersp() - 32*1024 + if !signal && _cgo_getstackbound != nil { + // Don't adjust if called from the signal handler. + // We are on the signal stack, not the pthread stack. + // (We could get the stack bounds from sigaltstack, but + // we're getting out of the signal handler very soon + // anyway. Not worth it.) + var bounds [2]uintptr + asmcgocall(_cgo_getstackbound, unsafe.Pointer(&bounds)) + // getstackbound is an unsupported no-op on Windows. + if bounds[0] != 0 { + gp.stack.lo = bounds[0] + gp.stack.hi = bounds[1] + } + } + gp.stackguard0 = gp.stack.lo + stackGuard // Should mark we are already in Go now. // Otherwise, we may call needm again when we get a signal, before cgocallbackg1, @@ -2156,14 +2176,9 @@ func oneNewExtraM() { // So that the destructor would invoke dropm while the non-Go thread is exiting. // This is much faster since it avoids expensive signal-related syscalls. // -// This always runs without a P, so //go:nowritebarrierrec is required. -// -// This may run with a different stack than was recorded in g0 (there is no -// call to callbackUpdateSystemStack prior to dropm), so this must be -// //go:nosplit to avoid the stack bounds check. +// NOTE: this always runs without a P, so, nowritebarrierrec required. // //go:nowritebarrierrec -//go:nosplit func dropm() { // Clear m and g, and return m to the extra list. // After the call to setg we can only call nosplit functions |