[compiler-rt] 9e66e58 - tsan: print signal num in errno spoiling reports

[Dmitry Vyukov via llvm-commits]

Author: Dmitry Vyukov
Date: 2022-03-18T16:12:11+01:00
New Revision: 9e66e5872c4a0f37731d2359c17ea24838b912d3

URL: https://github.com/llvm/llvm-project/commit/9e66e5872c4a0f37731d2359c17ea24838b912d3
DIFF: https://github.com/llvm/llvm-project/commit/9e66e5872c4a0f37731d2359c17ea24838b912d3.diff

LOG: tsan: print signal num in errno spoiling reports

For errno spoiling reports we only print the stack
where the signal handler is invoked. And the top
frame is the signal handler function, which is supposed
to give the info for debugging.
But in same cases the top frame can be some common thunk,
which does not give much info. E.g. for Go/cgo it's always
runtime.cgoSigtramp.

Print the signal number.
This is what we can easily gather and it may give at least
some hints regarding the issue.

Reviewed By: melver, vitalybuka

Differential Revision: https://reviews.llvm.org/D121979

Added: 
    

Modified: 
    compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp
    compiler-rt/lib/tsan/rtl/tsan_report.cpp
    compiler-rt/lib/tsan/rtl/tsan_report.h
    compiler-rt/lib/tsan/rtl/tsan_rtl.h
    compiler-rt/lib/tsan/rtl/tsan_rtl_report.cpp
    compiler-rt/test/tsan/signal_errno.cpp

Removed: 
    


################################################################################
diff  --git a/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp b/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp
index ea99c3843075a..d6021a754e71a 100644
--- a/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp
+++ b/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp
@@ -1964,13 +1964,14 @@ TSAN_INTERCEPTOR(int, pthread_sigmask, int how, const __sanitizer_sigset_t *set,
 
 namespace __tsan {
 
-static void ReportErrnoSpoiling(ThreadState *thr, uptr pc) {
+static void ReportErrnoSpoiling(ThreadState *thr, uptr pc, int sig) {
   VarSizeStackTrace stack;
   // StackTrace::GetNestInstructionPc(pc) is used because return address is
   // expected, OutputReport() will undo this.
   ObtainCurrentStack(thr, StackTrace::GetNextInstructionPc(pc), &stack);
   ThreadRegistryLock l(&ctx->thread_registry);
   ScopedReport rep(ReportTypeErrnoInSignal);
+  rep.SetSigNum(sig);
   if (!IsFiredSuppression(ctx, ReportTypeErrnoInSignal, stack)) {
     rep.AddStack(stack, true);
     OutputReport(thr, rep);
@@ -2037,7 +2038,7 @@ static void CallUserSignalHandler(ThreadState *thr, bool sync, bool acquire,
   // signal; and it looks too fragile to intercept all ways to reraise a signal.
   if (ShouldReport(thr, ReportTypeErrnoInSignal) && !sync && sig != SIGTERM &&
       errno != 99)
-    ReportErrnoSpoiling(thr, pc);
+    ReportErrnoSpoiling(thr, pc, sig);
   errno = saved_errno;
 }
 

diff  --git a/compiler-rt/lib/tsan/rtl/tsan_report.cpp b/compiler-rt/lib/tsan/rtl/tsan_report.cpp
index 10d9c761b8ee7..9f151279b601d 100644
--- a/compiler-rt/lib/tsan/rtl/tsan_report.cpp
+++ b/compiler-rt/lib/tsan/rtl/tsan_report.cpp
@@ -306,6 +306,9 @@ void PrintReport(const ReportDesc *rep) {
          (int)internal_getpid());
   Printf("%s", d.Default());
 
+  if (rep->typ == ReportTypeErrnoInSignal)
+    Printf("  Signal %u handler invoked at:\n", rep->signum);
+
   if (rep->typ == ReportTypeDeadlock) {
     char thrbuf[kThreadBufSize];
     Printf("  Cycle in lock order graph: ");

diff  --git a/compiler-rt/lib/tsan/rtl/tsan_report.h b/compiler-rt/lib/tsan/rtl/tsan_report.h
index 3b367f38e2667..718eacde7ec4c 100644
--- a/compiler-rt/lib/tsan/rtl/tsan_report.h
+++ b/compiler-rt/lib/tsan/rtl/tsan_report.h
@@ -108,6 +108,7 @@ class ReportDesc {
   Vector<Tid> unique_tids;
   ReportStack *sleep;
   int count;
+  int signum = 0;
 
   ReportDesc();
   ~ReportDesc();

diff  --git a/compiler-rt/lib/tsan/rtl/tsan_rtl.h b/compiler-rt/lib/tsan/rtl/tsan_rtl.h
index fbf02806e34b7..b472c0f77df18 100644
--- a/compiler-rt/lib/tsan/rtl/tsan_rtl.h
+++ b/compiler-rt/lib/tsan/rtl/tsan_rtl.h
@@ -376,6 +376,7 @@ class ScopedReportBase {
   void AddLocation(uptr addr, uptr size);
   void AddSleep(StackID stack_id);
   void SetCount(int count);
+  void SetSigNum(int sig);
 
   const ReportDesc *GetReport() const;
 

diff  --git a/compiler-rt/lib/tsan/rtl/tsan_rtl_report.cpp b/compiler-rt/lib/tsan/rtl/tsan_rtl_report.cpp
index 58949ead07b36..8f28b75f8f370 100644
--- a/compiler-rt/lib/tsan/rtl/tsan_rtl_report.cpp
+++ b/compiler-rt/lib/tsan/rtl/tsan_rtl_report.cpp
@@ -340,6 +340,8 @@ void ScopedReportBase::AddSleep(StackID stack_id) {
 
 void ScopedReportBase::SetCount(int count) { rep_->count = count; }
 
+void ScopedReportBase::SetSigNum(int sig) { rep_->signum = sig; }
+
 const ReportDesc *ScopedReportBase::GetReport() const { return rep_; }
 
 ScopedReport::ScopedReport(ReportType typ, uptr tag)

diff  --git a/compiler-rt/test/tsan/signal_errno.cpp b/compiler-rt/test/tsan/signal_errno.cpp
index 4d88bc5c420fe..5e6b1cef633e6 100644
--- a/compiler-rt/test/tsan/signal_errno.cpp
+++ b/compiler-rt/test/tsan/signal_errno.cpp
@@ -46,7 +46,7 @@ int main() {
 }
 
 // CHECK: WARNING: ThreadSanitizer: signal handler spoils errno
+// CHECK:   Signal 27 handler invoked at:
 // CHECK:     #0 MyHandler(int, {{(__)?}}siginfo{{(_t)?}}*, void*) {{.*}}signal_errno.cpp
 // CHECK:     main
 // CHECK: SUMMARY: ThreadSanitizer: signal handler spoils errno{{.*}}MyHandler
-