[sanitizer] VReport BeforeFork/AfterFork (llvm#111900)

Forks are common suspects for unusual sanitizer behavior.
It can be handy to see them without rebuild.

Author: vitalybuka

compiler-rt/lib/asan/asan_posix.cpp

@@ -149,6 +149,7 @@ void PlatformTSDDtor(void *tsd) {
 #  endif
 
 static void BeforeFork() {
+  VReport(2, "BeforeFork tid: %llu\n", GetTid());
   if (CAN_SANITIZE_LEAKS) {
     __lsan::LockGlobal();
   }
@@ -168,6 +169,7 @@ static void AfterFork(bool fork_child) {
   if (CAN_SANITIZE_LEAKS) {
     __lsan::UnlockGlobal();
   }
+  VReport(2, "AfterFork tid: %llu\n", GetTid());
 }
 
 void InstallAtForkHandler() {

compiler-rt/lib/dfsan/dfsan_custom.cpp

@@ -2859,13 +2859,15 @@ WRAPPER_ALIAS(__isoc99_sscanf, sscanf)
 WRAPPER_ALIAS(__isoc23_sscanf, sscanf)
 
 static void BeforeFork() {
+  VReport(2, "BeforeFork tid: %llu\n", GetTid());
   StackDepotLockBeforeFork();
   ChainedOriginDepotLockBeforeFork();
 }
 
 static void AfterFork(bool fork_child) {
   ChainedOriginDepotUnlockAfterFork(fork_child);
   StackDepotUnlockAfterFork(fork_child);
+  VReport(2, "AfterFork tid: %llu\n", GetTid());
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE

compiler-rt/lib/hwasan/hwasan_linux.cpp

@@ -528,6 +528,7 @@ uptr TagMemoryAligned(uptr p, uptr size, tag_t tag) {
 }
 
 static void BeforeFork() {
+  VReport(2, "BeforeFork tid: %llu\n", GetTid());
   if (CAN_SANITIZE_LEAKS) {
     __lsan::LockGlobal();
   }
@@ -547,6 +548,7 @@ static void AfterFork(bool fork_child) {
   if (CAN_SANITIZE_LEAKS) {
     __lsan::UnlockGlobal();
   }
+  VReport(2, "AfterFork tid: %llu\n", GetTid());
 }
 
 void HwasanInstallAtForkHandler() {

compiler-rt/lib/lsan/lsan_posix.cpp

@@ -97,6 +97,7 @@ void InstallAtExitCheckLeaks() {
 }
 
 static void BeforeFork() {
+  VReport(2, "BeforeFork tid: %llu\n", GetTid());
   LockGlobal();
   LockThreads();
   LockAllocator();
@@ -108,6 +109,7 @@ static void AfterFork(bool fork_child) {
   UnlockAllocator();
   UnlockThreads();
   UnlockGlobal();
+  VReport(2, "AfterFork tid: %llu\n", GetTid());
 }
 
 void InstallAtForkHandler() {

compiler-rt/lib/msan/msan_linux.cpp

@@ -302,6 +302,7 @@ void MsanTSDDtor(void *tsd) {
 #  endif
 
 static void BeforeFork() {
+  VReport(2, "BeforeFork tid: %llu\n", GetTid());
   // Usually we lock ThreadRegistry, but msan does not have one.
   LockAllocator();
   StackDepotLockBeforeFork();
@@ -313,6 +314,7 @@ static void AfterFork(bool fork_child) {
   StackDepotUnlockAfterFork(fork_child);
   UnlockAllocator();
   // Usually we unlock ThreadRegistry, but msan does not have one.
+  VReport(2, "AfterFork tid: %llu\n", GetTid());
 }
 
 void InstallAtForkHandler() {

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

@@ -806,6 +806,7 @@ int Finalize(ThreadState *thr) {
 
 #if !SANITIZER_GO
 void ForkBefore(ThreadState* thr, uptr pc) SANITIZER_NO_THREAD_SAFETY_ANALYSIS {
+  VReport(2, "BeforeFork tid: %llu\n", GetTid());
   GlobalProcessorLock();
   // Detaching from the slot makes OnUserFree skip writing to the shadow.
   // The slot will be locked so any attempts to use it will deadlock anyway.
@@ -847,6 +848,7 @@ static void ForkAfter(ThreadState* thr,
   SlotAttachAndLock(thr);
   SlotUnlock(thr);
   GlobalProcessorUnlock();
+  VReport(2, "AfterFork tid: %llu\n", GetTid());
 }
 
 void ForkParentAfter(ThreadState* thr, uptr pc) { ForkAfter(thr, false); }