TSAN: (Re)Mark shadow memory nondumpable after a reset

[wiktorg]

Summary

Shadow memory was not marked as non-dumpable after a reset resulting in process taking a very long time to generate a coredump.

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

 
 static const char kShadowMemoryMappingWarning[] =
     "FATAL: %s can not madvise shadow region [%zx, %zx] with %s (errno: %d)\n";
 static const char kShadowMemoryMappingHint[] =
     "HINT: if %s is not supported in your environment, you may set "
     "TSAN_OPTIONS=%s=0\n";
 
 #  if !SANITIZER_GO
-static void DontDumpShadow(uptr addr, uptr size) {
+void DontDumpShadow(uptr addr, uptr size) {
   if (common_flags()->use_madv_dontdump)
     if (!DontDumpShadowMemory(addr, size)) {
       Printf(kShadowMemoryMappingWarning, SanitizerToolName, addr, addr + size,
              "MADV_DONTDUMP", errno);
       Printf(kShadowMemoryMappingHint, "MADV_DONTDUMP", "use_madv_dontdump");
       Die();
     }
 }

compiler-rt/lib/tsan/rtl/tsan_rtl.h

#define GET_STACK_TRACE_FATAL(thr, pc) \
   ObtainCurrentStack(thr, pc, &stack); \
   stack.ReverseOrder();
 
 void MapShadow(uptr addr, uptr size);
 void MapThreadTrace(uptr addr, uptr size, const char *name);
 void DontNeedShadowFor(uptr addr, uptr size);
 void UnmapShadow(ThreadState *thr, uptr addr, uptr size);
 void InitializeShadowMemory();
+void DontDumpShadow(uptr addr, uptr size);
 void InitializeInterceptors();
 void InitializeLibIgnore();
 void InitializeDynamicAnnotations();
 
 void ForkBefore(ThreadState *thr, uptr pc);
 void ForkParentAfter(ThreadState *thr, uptr pc);
 void ForkChildAfter(ThreadState *thr, uptr pc, bool start_thread);
 

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

 #endif
 
 #if SANITIZER_WINDOWS
   auto resetFailed =
       !ZeroMmapFixedRegion(shadow_begin, shadow_end - shadow_begin);
 #else
   auto resetFailed =
       !MmapFixedSuperNoReserve(shadow_begin, shadow_end-shadow_begin, "shadow");
+#  if !SANITIZER_GO
+  DontDumpShadow(shadow_begin, shadow_end - shadow_begin);
+#  endif
 #endif
   if (resetFailed) {
     Printf("failed to reset shadow memory\n");
     Die();
   }
   DPrintf("Resetting meta shadow...\n");
   ctx->metamap.ResetClocks();
   StoreShadow(&ctx->last_spurious_race, Shadow::kEmpty);