diff options
Diffstat (limited to 'src/runtime/proc.go')
| -rw-r--r-- | src/runtime/proc.go | 30 |
1 files changed, 24 insertions, 6 deletions
diff --git a/src/runtime/proc.go b/src/runtime/proc.go index 6b96e97887..0fa0cf965e 100644 --- a/src/runtime/proc.go +++ b/src/runtime/proc.go @@ -1137,7 +1137,15 @@ func startTheWorldWithSema(emitTraceEvent bool) int64 { } // Called to start an M. +// +// This must not split the stack because we may not even have stack +// bounds set up yet. +// +// May run during STW (because it doesn't have a P yet), so write +// barriers are not allowed. +// //go:nosplit +//go:nowritebarrierrec func mstart() { _g_ := getg() @@ -1176,12 +1184,7 @@ func mstart1() { // Install signal handlers; after minit so that minit can // prepare the thread to be able to handle the signals. if _g_.m == &m0 { - // Create an extra M for callbacks on threads not created by Go. - if iscgo && !cgoHasExtraM { - cgoHasExtraM = true - newextram() - } - initsig(false) + mstartm0() } if fn := _g_.m.mstartfn; fn != nil { @@ -1198,6 +1201,21 @@ func mstart1() { schedule() } +// mstartm0 implements part of mstart1 that only runs on the m0. +// +// Write barriers are allowed here because we know the GC can't be +// running yet, so they'll be no-ops. +// +//go:yeswritebarrierrec +func mstartm0() { + // Create an extra M for callbacks on threads not created by Go. + if iscgo && !cgoHasExtraM { + cgoHasExtraM = true + newextram() + } + initsig(false) +} + // forEachP calls fn(p) for every P p when p reaches a GC safe point. // If a P is currently executing code, this will bring the P to a GC // safe point and execute fn on that P. If the P is not executing code |