[tsan] Don't delay SIGTRAP handler

Reviewers: eugenis, jfb

Subscribers: #sanitizers, llvm-commits

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D68604

llvm-svn: 373978

compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp

@@ -114,6 +114,7 @@ const int PTHREAD_MUTEX_RECURSIVE_NP = 2;
 const int EPOLL_CTL_ADD = 1;
 #endif
 const int SIGILL = 4;
+const int SIGTRAP = 5;
 const int SIGABRT = 6;
 const int SIGFPE = 8;
 const int SIGSEGV = 11;
@@ -1962,10 +1963,10 @@ void ProcessPendingSignals(ThreadState *thr) {
 }  // namespace __tsan
 
 static bool is_sync_signal(ThreadSignalContext *sctx, int sig) {
-  return sig == SIGSEGV || sig == SIGBUS || sig == SIGILL ||
-      sig == SIGABRT || sig == SIGFPE || sig == SIGPIPE || sig == SIGSYS ||
-      // If we are sending signal to ourselves, we must process it now.
-      (sctx && sig == sctx->int_signal_send);
+  return sig == SIGSEGV || sig == SIGBUS || sig == SIGILL || sig == SIGTRAP ||
+         sig == SIGABRT || sig == SIGFPE || sig == SIGPIPE || sig == SIGSYS ||
+         // If we are sending signal to ourselves, we must process it now.
+         (sctx && sig == sctx->int_signal_send);
 }
 
 void ALWAYS_INLINE rtl_generic_sighandler(bool sigact, int sig,

compiler-rt/test/sanitizer_common/TestCases/Linux/signal_trap_handler.cpp

@@ -0,0 +1,29 @@
+// RUN: %clangxx -O1 %s -o %t && %env_tool_opts=handle_sigtrap=1 %run %t 2>&1 | FileCheck %s
+
+#include <assert.h>
+#include <signal.h>
+#include <stdio.h>
+
+int handled;
+
+void handler(int signo, siginfo_t *info, void *uctx) {
+  handled = 1;
+}
+
+int main() {
+  struct sigaction a = {}, old = {};
+  a.sa_sigaction = handler;
+  a.sa_flags = SA_SIGINFO;
+  sigaction(SIGTRAP, &a, &old);
+
+  a = {};
+  sigaction(SIGTRAP, 0, &a);
+  assert(a.sa_sigaction == handler);
+  assert(a.sa_flags & SA_SIGINFO);
+
+  __builtin_debugtrap();
+  assert(handled);
+  fprintf(stderr, "HANDLED %d\n", handled);
+}
+
+// CHECK: HANDLED 1