[llvm-branch-commits] [compiler-rt] [TSan] Defer symbolization in AddStack and AddSleep to SymbolizeStackElems (PR #228795)

[Vitaly Buka via llvm-branch-commits]

https://github.com/vitalybuka updated https://github.com/llvm/llvm-project/pull/228795

>From 61105abfe9f7b959b62725744c1c4920add05246 Mon Sep 17 00:00:00 2001
From: Vitaly Buka <vitalybuka at google.com>
Date: Sat, 3 Oct 2026 19:01:00 -0700
Subject: [PATCH] [TSan] Defer symbolization in AddStack and AddSleep to
 SymbolizeStackElems

PR #151495 delayed symbolization for memory accesses, locations,
threads, and mutexes until OutputReport (after ThreadRegistryLock is
released), but missed ScopedReport::AddStack and ScopedReport::AddSleep.
As a result, ReportRace (via AddSleep) and ReportMutexMisuse,
ReportDeadlock, and ReportDestroyLocked (via AddStack) still invoked the
symbolizer while holding ThreadRegistryLock.

Store the unsymbolized stack traces and sleep stack ID in ReportDesc and
symbolize them in ScopedReport::SymbolizeStackElems().

Assisted-by: Gemini

Pull Request: https://github.com/llvm/llvm-project/pull/228795
---
 compiler-rt/lib/tsan/rtl/tsan_report.h       |  7 +++++++
 compiler-rt/lib/tsan/rtl/tsan_rtl_report.cpp | 19 +++++++++++++++----
 2 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/compiler-rt/lib/tsan/rtl/tsan_report.h b/compiler-rt/lib/tsan/rtl/tsan_report.h
index a664bc5d49332..13171aa270684 100644
--- a/compiler-rt/lib/tsan/rtl/tsan_report.h
+++ b/compiler-rt/lib/tsan/rtl/tsan_report.h
@@ -111,11 +111,17 @@ struct AddedLocationAddr {
   usize locs_idx = 0;
 };
 
+struct AddedStack {
+  StackTrace stack_trace;
+  bool suppressable = false;
+};
+
 class ReportDesc {
  public:
   ReportType typ = ReportTypeRace;
   uptr tag = kExternalTagNone;
   Vector<ReportStack*> stacks;
+  Vector<AddedStack> added_stacks;
   Vector<ReportMop*> mops;
   Vector<ReportLocation*> locs;
   Vector<AddedLocationAddr> added_location_addrs;
@@ -123,6 +129,7 @@ class ReportDesc {
   Vector<ReportThread*> threads;
   Vector<Tid> unique_tids;
   ReportStack* sleep = nullptr;
+  StackID sleep_stack_id = 0;
   int count = 0;
   int signum = 0;
 
diff --git a/compiler-rt/lib/tsan/rtl/tsan_rtl_report.cpp b/compiler-rt/lib/tsan/rtl/tsan_rtl_report.cpp
index 52a462617ecb4..5644456bb2864 100644
--- a/compiler-rt/lib/tsan/rtl/tsan_rtl_report.cpp
+++ b/compiler-rt/lib/tsan/rtl/tsan_rtl_report.cpp
@@ -173,9 +173,7 @@ ScopedReport::ScopedReport(ReportType typ, uptr tag) {
 ScopedReport::~ScopedReport() { DestroyAndFree(rep_); }
 
 void ScopedReport::AddStack(StackTrace stack, bool suppressable) {
-  ReportStack **rs = rep_->stacks.PushBack();
-  *rs = SymbolizeStack(stack);
-  (*rs)->suppressable = suppressable;
+  rep_->added_stacks.PushBack({stack, suppressable});
 }
 
 void ScopedReport::AddMemoryAccess(uptr addr, uptr external_tag, Shadow s,
@@ -202,6 +200,15 @@ void ScopedReport::AddMemoryAccess(uptr addr, uptr external_tag, Shadow s,
 }
 
 void ScopedReport::SymbolizeStackElems() {
+  // symbolize stacks
+  for (usize i = 0, size = rep_->added_stacks.Size(); i < size; i++) {
+    AddedStack& as = rep_->added_stacks[i];
+    ReportStack* rs = SymbolizeStack(as.stack_trace);
+    if (rs)
+      rs->suppressable = as.suppressable;
+    rep_->stacks.PushBack(rs);
+  }
+
   // symbolize memory ops
   for (usize i = 0, size = rep_->mops.Size(); i < size; i++) {
     ReportMop *mop = rep_->mops[i];
@@ -249,6 +256,10 @@ void ScopedReport::SymbolizeStackElems() {
     ReportMutex *rm = rep_->mutexes[i];
     rm->stack = SymbolizeStackId(rm->stack_id);
   }
+
+#if !SANITIZER_GO
+  rep_->sleep = SymbolizeStackId(rep_->sleep_stack_id);
+#endif
 }
 
 void ScopedReport::AddUniqueTid(Tid unique_tid) {
@@ -381,7 +392,7 @@ void ScopedReport::AddLocation(uptr addr, uptr size) {
 
 #if !SANITIZER_GO
 void ScopedReport::AddSleep(StackID stack_id) {
-  rep_->sleep = SymbolizeStackId(stack_id);
+  rep_->sleep_stack_id = stack_id;
 }
 #endif