diff --git a/src/runtime/cgocall.go b/src/runtime/cgocall.go index 8ffb48a888..2626216f95 100644 --- a/src/runtime/cgocall.go +++ b/src/runtime/cgocall.go @@ -212,6 +212,8 @@ 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 @@ -227,15 +229,20 @@ 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)) @@ -244,6 +251,11 @@ 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) @@ -323,10 +335,6 @@ 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 diff --git a/src/runtime/crash_cgo_test.go b/src/runtime/crash_cgo_test.go index 7d25c51aa2..5729942cee 100644 --- a/src/runtime/crash_cgo_test.go +++ b/src/runtime/crash_cgo_test.go @@ -282,6 +282,15 @@ func TestCgoTracebackContext(t *testing.T) { } } +func TestCgoTracebackContextPreemption(t *testing.T) { + t.Parallel() + got := runTestProg(t, "testprogcgo", "TracebackContextPreemption") + want := "OK\n" + if got != want { + t.Errorf("expected %q got %v", want, got) + } +} + func testCgoPprof(t *testing.T, buildArg, runArg, top, bottom string) { t.Parallel() if runtime.GOOS != "linux" || (runtime.GOARCH != "amd64" && runtime.GOARCH != "ppc64le") { diff --git a/src/runtime/testdata/testprogcgo/tracebackctxt.go b/src/runtime/testdata/testprogcgo/tracebackctxt.go index 51fa4ad25c..62ff8eccd6 100644 --- a/src/runtime/testdata/testprogcgo/tracebackctxt.go +++ b/src/runtime/testdata/testprogcgo/tracebackctxt.go @@ -2,8 +2,6 @@ // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. -// The __attribute__((weak)) used below doesn't seem to work on Windows. - package main // Test the context argument to SetCgoTraceback. @@ -14,20 +12,24 @@ package main extern void C1(void); extern void C2(void); extern void tcContext(void*); +extern void tcContextSimple(void*); extern void tcTraceback(void*); extern void tcSymbolizer(void*); extern int getContextCount(void); +extern void TracebackContextPreemptionCallGo(int); */ import "C" import ( "fmt" "runtime" + "sync" "unsafe" ) func init() { register("TracebackContext", TracebackContext) + register("TracebackContextPreemption", TracebackContextPreemption) } var tracebackOK bool @@ -105,3 +107,30 @@ wantLoop: tracebackOK = false } } + +// Issue 47441. +func TracebackContextPreemption() { + runtime.SetCgoTraceback(0, unsafe.Pointer(C.tcTraceback), unsafe.Pointer(C.tcContextSimple), unsafe.Pointer(C.tcSymbolizer)) + + const funcs = 10 + const calls = 1e5 + var wg sync.WaitGroup + for i := 0; i < funcs; i++ { + wg.Add(1) + go func(i int) { + defer wg.Done() + for j := 0; j < calls; j++ { + C.TracebackContextPreemptionCallGo(C.int(i*calls + j)) + } + }(i) + } + wg.Wait() + + fmt.Println("OK") +} + +//export TracebackContextPreemptionGoFunction +func TracebackContextPreemptionGoFunction(i C.int) { + // Do some busy work. + fmt.Sprintf("%d\n", i) +} diff --git a/src/runtime/testdata/testprogcgo/tracebackctxt_c.c b/src/runtime/testdata/testprogcgo/tracebackctxt_c.c index 900cada0d3..910cb7b899 100644 --- a/src/runtime/testdata/testprogcgo/tracebackctxt_c.c +++ b/src/runtime/testdata/testprogcgo/tracebackctxt_c.c @@ -11,6 +11,7 @@ // Functions exported from Go. extern void G1(void); extern void G2(void); +extern void TracebackContextPreemptionGoFunction(int); void C1() { G1(); @@ -62,10 +63,17 @@ void tcContext(void* parg) { } } +void tcContextSimple(void* parg) { + struct cgoContextArg* arg = (struct cgoContextArg*)(parg); + if (arg->context == 0) { + arg->context = 1; + } +} + void tcTraceback(void* parg) { int base, i; struct cgoTracebackArg* arg = (struct cgoTracebackArg*)(parg); - if (arg->context == 0) { + if (arg->context == 0 && arg->sigContext == 0) { // This shouldn't happen in this program. abort(); } @@ -89,3 +97,7 @@ void tcSymbolizer(void *parg) { arg->func = "cFunction"; arg->lineno = arg->pc + (arg->more << 16); } + +void TracebackContextPreemptionCallGo(int i) { + TracebackContextPreemptionGoFunction(i); +}