runtime/cgo: add tsan sync for traceback function

Change-Id: Ifb8d64f18b67c8b712feec29ffb6719c6e9718ec
Reviewed-on: https://go-review.googlesource.com/c/go/+/474198
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Bryan Mills <bcmills@google.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>

diff --git a/misc/cgo/testsanitizers/testdata/tsan13.go b/misc/cgo/testsanitizers/testdata/tsan13.go
new file mode 100644 (file)
index 0000000..ebdf635
--- /dev/null
+++ b/misc/cgo/testsanitizers/testdata/tsan13.go
@@ -0,0 +1,90 @@
+// Copyright 2023 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+// This program failed when run under the C/C++ ThreadSanitizer.
+// There was no TSAN synchronization for the call to the cgo
+// traceback routine.
+
+/*
+#cgo CFLAGS: -g -fsanitize=thread
+#cgo LDFLAGS: -g -fsanitize=thread
+
+#include <pthread.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <sys/time.h>
+#include <unistd.h>
+
+struct tracebackArg {
+       uintptr_t  Context;
+       uintptr_t  SigContext;
+       uintptr_t* Buf;
+       uintptr_t  Max;
+};
+
+void tsanTraceback(struct tracebackArg *arg) {
+       arg->Buf[0] = 0;
+}
+
+static void* spin(void *arg) {
+       size_t n;
+       struct timeval tvstart, tvnow;
+       int diff;
+       void *prev;
+       void *cur;
+
+       prev = NULL;
+       gettimeofday(&tvstart, NULL);
+       for (n = 0; n < 1<<20; n++) {
+               cur = malloc(n);
+               free(prev);
+               prev = cur;
+
+               gettimeofday(&tvnow, NULL);
+               diff = (tvnow.tv_sec - tvstart.tv_sec) * 1000 * 1000 + (tvnow.tv_usec - tvstart.tv_usec);
+
+               // Profile frequency is 100Hz so we should definitely
+               // get some signals in 50 milliseconds.
+               if (diff > 50 * 1000) {
+                       break;
+               }
+       }
+
+       free(prev);
+
+       return NULL;
+}
+
+static void runThreads(int n) {
+       pthread_t ids[64];
+       int i;
+
+       if (n > 64) {
+               n = 64;
+       }
+       for (i = 0; i < n; i++) {
+               pthread_create(&ids[i], NULL, spin, NULL);
+       }
+       for (i = 0; i < n; i++) {
+               pthread_join(ids[i], NULL);
+       }
+}
+*/
+import "C"
+
+import (
+       "io"
+       "runtime"
+       "runtime/pprof"
+       "unsafe"
+)
+
+func main() {
+       runtime.SetCgoTraceback(0, unsafe.Pointer(C.tsanTraceback), nil, nil)
+       pprof.StartCPUProfile(io.Discard)
+       C.runThreads(C.int(runtime.GOMAXPROCS(0)))
+       pprof.StopCPUProfile()
+}

diff --git a/misc/cgo/testsanitizers/tsan_test.go b/misc/cgo/testsanitizers/tsan_test.go
index 00ad313b9cb6d20d2891e9a7606479f9442505d5..f65d842363242e40a7ec417a10dda0c3cbb628f9 100644 (file)
--- a/misc/cgo/testsanitizers/tsan_test.go
+++ b/misc/cgo/testsanitizers/tsan_test.go
@@ -46,6 +46,7 @@ func TestTSAN(t *testing.T) {
                {src: "tsan10.go", needsRuntime: true},
                {src: "tsan11.go", needsRuntime: true},
                {src: "tsan12.go", needsRuntime: true},
+               {src: "tsan13.go", needsRuntime: true},
        }
        for _, tc := range cases {
                tc := tc
@@ -63,6 +64,9 @@ func TestTSAN(t *testing.T) {
                        if tc.needsRuntime {
                                config.skipIfRuntimeIncompatible(t)
                        }
+                       // If we don't see halt_on_error, the program
+                       // will only exit non-zero if we call C.exit.
+                       cmd.Env = append(cmd.Environ(), "TSAN_OPTIONS=halt_on_error=1")
                        mustRun(t, cmd)
                })
        }

diff --git a/src/runtime/cgo/gcc_traceback.c b/src/runtime/cgo/gcc_traceback.c
index 053430047bf0d8025f1a7688a8efadaa18009481..c6643a1e53adbeccd4fd61c4411dba13ac00a78c 100644 (file)
--- a/src/runtime/cgo/gcc_traceback.c
+++ b/src/runtime/cgo/gcc_traceback.c
@@ -39,6 +39,8 @@ x_cgo_callers(uintptr_t sig, void *info, void *context, void (*cgoTraceback)(str
         __msan_unpoison(&arg, sizeof arg);
 #endif
 
+       _cgo_tsan_acquire();
        (*cgoTraceback)(&arg);
+       _cgo_tsan_release();
        sigtramp(sig, info, context);
 }