tsan: remember and print function that installed at_exit callbacks
Sometimes stacks for at_exit callbacks don't include any of the user functions/files.
For example, a race with a global std container destructor will only contain
the container type name and our at_exit_wrapper function. No signs what global variable
this is.
Remember and include in reports the function that installed the at_exit callback.
This should give glues as to what variable is being destroyed.
Depends on D114606.
Reviewed By: vitalybuka, melver
Differential Revision: https://reviews.llvm.org/D114607
GitOrigin-RevId: a1dc97e47231e737e1252d1aeb159764dbaed977
diff --git a/lib/tsan/rtl/tsan_interceptors_posix.cpp b/lib/tsan/rtl/tsan_interceptors_posix.cpp
index 9d17e9b..280db4a 100644
--- a/lib/tsan/rtl/tsan_interceptors_posix.cpp
+++ b/lib/tsan/rtl/tsan_interceptors_posix.cpp
@@ -177,6 +177,7 @@
struct AtExitCtx {
void (*f)();
void *arg;
+ uptr pc;
};
// InterceptorContext holds all global data required for interceptors.
@@ -367,7 +368,10 @@
return BLOCK_REAL(pause)(fake);
}
-static void at_exit_wrapper() {
+// Note: we specifically call the function in such strange way
+// with "installed_at" because in reports it will appear between
+// callback frames and the frame that installed the callback.
+static void at_exit_callback_installed_at() {
AtExitCtx *ctx;
{
// Ensure thread-safety.
@@ -379,15 +383,21 @@
interceptor_ctx()->AtExitStack.PopBack();
}
- Acquire(cur_thread(), (uptr)0, (uptr)ctx);
+ ThreadState *thr = cur_thread();
+ Acquire(thr, ctx->pc, (uptr)ctx);
+ FuncEntry(thr, ctx->pc);
((void(*)())ctx->f)();
+ FuncExit(thr);
Free(ctx);
}
-static void cxa_at_exit_wrapper(void *arg) {
- Acquire(cur_thread(), 0, (uptr)arg);
+static void cxa_at_exit_callback_installed_at(void *arg) {
+ ThreadState *thr = cur_thread();
AtExitCtx *ctx = (AtExitCtx*)arg;
+ Acquire(thr, ctx->pc, (uptr)arg);
+ FuncEntry(thr, ctx->pc);
((void(*)(void *arg))ctx->f)(ctx->arg);
+ FuncExit(thr);
Free(ctx);
}
@@ -401,7 +411,7 @@
// We want to setup the atexit callback even if we are in ignored lib
// or after fork.
SCOPED_INTERCEPTOR_RAW(atexit, f);
- return setup_at_exit_wrapper(thr, pc, (void(*)())f, 0, 0);
+ return setup_at_exit_wrapper(thr, GET_CALLER_PC(), (void (*)())f, 0, 0);
}
#endif
@@ -409,7 +419,7 @@
if (in_symbolizer())
return 0;
SCOPED_TSAN_INTERCEPTOR(__cxa_atexit, f, arg, dso);
- return setup_at_exit_wrapper(thr, pc, (void(*)())f, arg, dso);
+ return setup_at_exit_wrapper(thr, GET_CALLER_PC(), (void (*)())f, arg, dso);
}
static int setup_at_exit_wrapper(ThreadState *thr, uptr pc, void(*f)(),
@@ -417,6 +427,7 @@
auto *ctx = New<AtExitCtx>();
ctx->f = f;
ctx->arg = arg;
+ ctx->pc = pc;
Release(thr, pc, (uptr)ctx);
// Memory allocation in __cxa_atexit will race with free during exit,
// because we do not see synchronization around atexit callback list.
@@ -432,25 +443,27 @@
// due to atexit_mu held on exit from the calloc interceptor.
ScopedIgnoreInterceptors ignore;
- res = REAL(__cxa_atexit)((void (*)(void *a))at_exit_wrapper, 0, 0);
+ res = REAL(__cxa_atexit)((void (*)(void *a))at_exit_callback_installed_at,
+ 0, 0);
// Push AtExitCtx on the top of the stack of callback functions
if (!res) {
interceptor_ctx()->AtExitStack.PushBack(ctx);
}
} else {
- res = REAL(__cxa_atexit)(cxa_at_exit_wrapper, ctx, dso);
+ res = REAL(__cxa_atexit)(cxa_at_exit_callback_installed_at, ctx, dso);
}
ThreadIgnoreEnd(thr);
return res;
}
#if !SANITIZER_MAC && !SANITIZER_NETBSD
-static void on_exit_wrapper(int status, void *arg) {
+static void on_exit_callback_installed_at(int status, void *arg) {
ThreadState *thr = cur_thread();
- uptr pc = 0;
- Acquire(thr, pc, (uptr)arg);
AtExitCtx *ctx = (AtExitCtx*)arg;
+ Acquire(thr, ctx->pc, (uptr)arg);
+ FuncEntry(thr, ctx->pc);
((void(*)(int status, void *arg))ctx->f)(status, ctx->arg);
+ FuncExit(thr);
Free(ctx);
}
@@ -461,11 +474,12 @@
auto *ctx = New<AtExitCtx>();
ctx->f = (void(*)())f;
ctx->arg = arg;
+ ctx->pc = GET_CALLER_PC();
Release(thr, pc, (uptr)ctx);
// Memory allocation in __cxa_atexit will race with free during exit,
// because we do not see synchronization around atexit callback list.
ThreadIgnoreBegin(thr, pc);
- int res = REAL(on_exit)(on_exit_wrapper, ctx);
+ int res = REAL(on_exit)(on_exit_callback_installed_at, ctx);
ThreadIgnoreEnd(thr);
return res;
}
diff --git a/test/tsan/atexit4.cpp b/test/tsan/atexit4.cpp
index 325f24b..7102b3a 100644
--- a/test/tsan/atexit4.cpp
+++ b/test/tsan/atexit4.cpp
@@ -31,4 +31,5 @@
// CHECK: #0 thread
// CHECK: Previous write of size 4
// CHECK: #0 race
-// CHECK: #1 at_exit_wrapper
+// CHECK: #1 at_exit_callback_installed_at
+// CHECK: #2 X
diff --git a/test/tsan/atexit5.cpp b/test/tsan/atexit5.cpp
index 90649cc..a784bc6 100644
--- a/test/tsan/atexit5.cpp
+++ b/test/tsan/atexit5.cpp
@@ -23,4 +23,5 @@
// CHECK: Write of size 8
// The exact spelling and number of std frames is hard to guess.
// CHECK: unique_ptr
-// CHECK: #{{1|2}} cxa_at_exit_wrapper
+// CHECK: #{{1|2}} cxa_at_exit_callback_installed_at
+// CHECK: #{{2|3}} __cxx_global_var_init
diff --git a/test/tsan/on_exit.cpp b/test/tsan/on_exit.cpp
index 5dd5bfa..05e19ad 100644
--- a/test/tsan/on_exit.cpp
+++ b/test/tsan/on_exit.cpp
@@ -28,4 +28,5 @@
// CHECK: WARNING: ThreadSanitizer: data race
// CHECK: Write of size 8
// CHECK: #0 on_exit_callback
-// CHECK: #1 on_exit_wrapper
+// CHECK: #1 on_exit_callback_installed_at
+// CHECK: #2 main
