diff options
| author | Bill Zissimopoulos <billziss@navimatics.com> | 2018-06-03 17:25:29 +0000 |
|---|---|---|
| committer | Ian Lance Taylor <iant@golang.org> | 2018-06-05 13:50:06 +0000 |
| commit | bb0fae603bd19e096e38c3321d95bf114f40dcff (patch) | |
| tree | b0c45e56cf68249c65c4cdde293e640dcb5049f4 /src/runtime/proc.go | |
| parent | 4a2bec9726eca30cd499695f210fe5e26f949229 (diff) | |
| download | go-bb0fae603bd19e096e38c3321d95bf114f40dcff.tar.xz | |
runtime: handle windows callback on non-go thread
Adds an extra M in mstartm0 and accounts for it in checkdead. This allows Windows callbacks created with syscall.NewCallback and syscall.NewCallbackCDecl to be called on a non-Go thread.
Fixes #6751
Change-Id: I57626bc009a6370b9ca0827ab64b14b01dec39d4
GitHub-Last-Rev: d429e3eed923640edab580bdb47fcb81e75dbfe8
GitHub-Pull-Request: golang/go#25575
Reviewed-on: https://go-review.googlesource.com/114802
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Diffstat (limited to 'src/runtime/proc.go')
| -rw-r--r-- | src/runtime/proc.go | 21 |
1 files changed, 18 insertions, 3 deletions
diff --git a/src/runtime/proc.go b/src/runtime/proc.go index 9f4feebfd7..9908951544 100644 --- a/src/runtime/proc.go +++ b/src/runtime/proc.go @@ -1293,7 +1293,9 @@ func mstart1() { //go:yeswritebarrierrec func mstartm0() { // Create an extra M for callbacks on threads not created by Go. - if iscgo && !cgoHasExtraM { + // An extra M is also needed on Windows for callbacks created by + // syscall.NewCallback. See issue #6751 for details. + if (iscgo || GOOS == "windows") && !cgoHasExtraM { cgoHasExtraM = true newextram() } @@ -1618,8 +1620,12 @@ func allocm(_p_ *p, fn func()) *m { // put the m back on the list. //go:nosplit func needm(x byte) { - if iscgo && !cgoHasExtraM { + if (iscgo || GOOS == "windows") && !cgoHasExtraM { // Can happen if C/C++ code calls Go from a global ctor. + // Can also happen on Windows if a global ctor uses a + // callback created by syscall.NewCallback. See issue #6751 + // for details. + // // Can not throw, because scheduler is not initialized yet. write(2, unsafe.Pointer(&earlycgocallback[0]), int32(len(earlycgocallback))) exit(1) @@ -4215,8 +4221,17 @@ func checkdead() { return } + // If we are not running under cgo, but we have an extra M then account + // for it. (It is possible to have an extra M on Windows without cgo to + // accommodate callbacks created by syscall.NewCallback. See issue #6751 + // for details.) + var run0 int32 + if !iscgo && cgoHasExtraM { + run0 = 1 + } + run := mcount() - sched.nmidle - sched.nmidlelocked - sched.nmsys - if run > 0 { + if run > run0 { return } if run < 0 { |