diff options
Diffstat (limited to 'src/runtime/cgocall.go')
| -rw-r--r-- | src/runtime/cgocall.go | 20 |
1 files changed, 14 insertions, 6 deletions
diff --git a/src/runtime/cgocall.go b/src/runtime/cgocall.go index 479878e6d2..2f3c609907 100644 --- a/src/runtime/cgocall.go +++ b/src/runtime/cgocall.go @@ -213,6 +213,8 @@ func cgocallbackg(fn, frame unsafe.Pointer, ctxt uintptr) { // a different M. The call to unlockOSThread is in unwindm. lockOSThread() + checkm := gp.m + // Save current syscall parameters, so m.syscall can be // used again if callback decide to make syscall. syscall := gp.m.syscall @@ -228,15 +230,20 @@ func cgocallbackg(fn, frame unsafe.Pointer, ctxt uintptr) { osPreemptExtExit(gp.m) - cgocallbackg1(fn, frame, ctxt) + cgocallbackg1(fn, frame, ctxt) // will call unlockOSThread // At this point unlockOSThread has been called. // The following code must not change to a different m. // This is enforced by checking incgo in the schedule function. + gp.m.incgo = true + + if gp.m != checkm { + throw("m changed unexpectedly in cgocallbackg") + } + osPreemptExtEnter(gp.m) - gp.m.incgo = true // going back to cgo call reentersyscall(savedpc, uintptr(savedsp)) @@ -245,6 +252,11 @@ func cgocallbackg(fn, frame unsafe.Pointer, ctxt uintptr) { func cgocallbackg1(fn, frame unsafe.Pointer, ctxt uintptr) { gp := getg() + + // When we return, undo the call to lockOSThread in cgocallbackg. + // We must still stay on the same m. + defer unlockOSThread() + if gp.m.needextram || atomic.Load(&extraMWaiters) > 0 { gp.m.needextram = false systemstack(newextram) @@ -324,10 +336,6 @@ func unwindm(restore *bool) { releasem(mp) } - - // Undo the call to lockOSThread in cgocallbackg. - // We must still stay on the same m. - unlockOSThread() } // called from assembly |