[compiler-rt] 20ee72d - tsan: don't call dlsym during exit

[Dmitry Vyukov via llvm-commits]

Author: Dmitry Vyukov
Date: 2021-09-22T07:11:59+02:00
New Revision: 20ee72d4ccb17c6f32641c690fa129475427ae45

URL: https://github.com/llvm/llvm-project/commit/20ee72d4ccb17c6f32641c690fa129475427ae45
DIFF: https://github.com/llvm/llvm-project/commit/20ee72d4ccb17c6f32641c690fa129475427ae45.diff

LOG: tsan: don't call dlsym during exit

dlsym calls into dynamic linker which calls malloc and other things.
It's problematic to do it during the actual exit, because
it can happen from a singal handler or from within the runtime
after we reported the first bug, etc.
See https://github.com/google/sanitizers/issues/1440 for an example
(captured in the added test).
Initialize the callbacks during startup instead.

Depends on D110159.

Reviewed By: vitalybuka

Differential Revision: https://reviews.llvm.org/D110166

Added: 
    compiler-rt/test/tsan/signal_exit.cpp

Modified: 
    compiler-rt/lib/tsan/rtl/tsan_interface.h
    compiler-rt/lib/tsan/rtl/tsan_platform_posix.cpp
    compiler-rt/lib/tsan/rtl/tsan_rtl.cpp
    compiler-rt/lib/tsan/rtl/tsan_rtl.h

Removed: 
    


################################################################################
diff  --git a/compiler-rt/lib/tsan/rtl/tsan_interface.h b/compiler-rt/lib/tsan/rtl/tsan_interface.h
index 482da73510ef..711f064174c2 100644
--- a/compiler-rt/lib/tsan/rtl/tsan_interface.h
+++ b/compiler-rt/lib/tsan/rtl/tsan_interface.h
@@ -417,12 +417,6 @@ SANITIZER_INTERFACE_ATTRIBUTE
 void __tsan_go_atomic64_compare_exchange(ThreadState *thr, uptr cpc, uptr pc,
                                          u8 *a);
 
-SANITIZER_INTERFACE_ATTRIBUTE
-void __tsan_on_initialize();
-
-SANITIZER_INTERFACE_ATTRIBUTE
-int __tsan_on_finalize(int failed);
-
 }  // extern "C"
 
 }  // namespace __tsan

diff  --git a/compiler-rt/lib/tsan/rtl/tsan_platform_posix.cpp b/compiler-rt/lib/tsan/rtl/tsan_platform_posix.cpp
index 13d80aa79221..55c2919ca4e0 100644
--- a/compiler-rt/lib/tsan/rtl/tsan_platform_posix.cpp
+++ b/compiler-rt/lib/tsan/rtl/tsan_platform_posix.cpp
@@ -14,12 +14,14 @@
 #include "sanitizer_common/sanitizer_platform.h"
 #if SANITIZER_POSIX
 
-#include "sanitizer_common/sanitizer_common.h"
-#include "sanitizer_common/sanitizer_errno.h"
-#include "sanitizer_common/sanitizer_libc.h"
-#include "sanitizer_common/sanitizer_procmaps.h"
-#include "tsan_platform.h"
-#include "tsan_rtl.h"
+#  include <dlfcn.h>
+
+#  include "sanitizer_common/sanitizer_common.h"
+#  include "sanitizer_common/sanitizer_errno.h"
+#  include "sanitizer_common/sanitizer_libc.h"
+#  include "sanitizer_common/sanitizer_procmaps.h"
+#  include "tsan_platform.h"
+#  include "tsan_rtl.h"
 
 namespace __tsan {
 
@@ -70,6 +72,11 @@ void InitializeShadowMemory() {
       meta, meta + meta_size, meta_size >> 30);
 
   InitializeShadowMemoryPlatform();
+
+  on_initialize = reinterpret_cast<void (*)(void)>(
+      dlsym(RTLD_DEFAULT, "__tsan_on_initialize"));
+  on_finalize =
+      reinterpret_cast<int (*)(int)>(dlsym(RTLD_DEFAULT, "__tsan_on_finalize"));
 }
 
 static bool TryProtectRange(uptr beg, uptr end) {

diff  --git a/compiler-rt/lib/tsan/rtl/tsan_rtl.cpp b/compiler-rt/lib/tsan/rtl/tsan_rtl.cpp
index f13a05066652..12211cff1c02 100644
--- a/compiler-rt/lib/tsan/rtl/tsan_rtl.cpp
+++ b/compiler-rt/lib/tsan/rtl/tsan_rtl.cpp
@@ -36,6 +36,11 @@ extern "C" void __tsan_resume() {
 
 namespace __tsan {
 
+#if !SANITIZER_GO
+void (*on_initialize)(void);
+int (*on_finalize)(int);
+#endif
+
 #if !SANITIZER_GO && !SANITIZER_MAC
 __attribute__((tls_model("initial-exec")))
 THREADLOCAL char cur_thread_placeholder[sizeof(ThreadState)] ALIGNED(64);
@@ -52,17 +57,16 @@ void OnInitialize();
 SANITIZER_WEAK_CXX_DEFAULT_IMPL
 bool OnFinalize(bool failed) {
 #if !SANITIZER_GO
-  if (auto *ptr = dlsym(RTLD_DEFAULT, "__tsan_on_finalize"))
-    return reinterpret_cast<decltype(&__tsan_on_finalize)>(ptr)(failed);
+  if (on_finalize)
+    return on_finalize(failed);
 #endif
   return failed;
 }
 SANITIZER_WEAK_CXX_DEFAULT_IMPL
 void OnInitialize() {
 #if !SANITIZER_GO
-  if (auto *ptr = dlsym(RTLD_DEFAULT, "__tsan_on_initialize")) {
-    return reinterpret_cast<decltype(&__tsan_on_initialize)>(ptr)();
-  }
+  if (on_initialize)
+    on_initialize();
 #endif
 }
 #endif

diff  --git a/compiler-rt/lib/tsan/rtl/tsan_rtl.h b/compiler-rt/lib/tsan/rtl/tsan_rtl.h
index 1eb9b8c13823..af149460e06b 100644
--- a/compiler-rt/lib/tsan/rtl/tsan_rtl.h
+++ b/compiler-rt/lib/tsan/rtl/tsan_rtl.h
@@ -985,6 +985,11 @@ void TraceTime(ThreadState *thr);
 
 }  // namespace v3
 
+#if !SANITIZER_GO
+extern void (*on_initialize)(void);
+extern int (*on_finalize)(int);
+#endif
+
 }  // namespace __tsan
 
 #endif  // TSAN_RTL_H

diff  --git a/compiler-rt/test/tsan/signal_exit.cpp b/compiler-rt/test/tsan/signal_exit.cpp
new file mode 100644
index 000000000000..0c4444d2c409
--- /dev/null
+++ b/compiler-rt/test/tsan/signal_exit.cpp
@@ -0,0 +1,22 @@
+// RUN: %clang_tsan -O1 %s -o %t && %run %t 2>&1 | FileCheck %s
+#include "test.h"
+#include <signal.h>
+#include <sys/types.h>
+
+static void handler(int, siginfo_t *, void *) {
+  write(2, "SIGNAL\n", 7);
+  // CHECK: SIGNAL
+  _exit(0);
+  // CHECK-NOT: ThreadSanitizer: signal-unsafe call
+}
+
+int main() {
+  struct sigaction act = {};
+  act.sa_sigaction = &handler;
+  act.sa_flags = SA_SIGINFO;
+  sigaction(SIGPROF, &act, 0);
+  raise(SIGPROF);
+  fprintf(stderr, "DONE\n");
+  // CHECK-NOT: DONE
+  return 0;
+}