[asan] Prevent printing invalid parent thread

[vitalybuka]

By default reuse can happend only after
UINT32_MAX threads, so it's almost NFC.

[llvmbot]

@llvm/pr-subscribers-compiler-rt-sanitizer

Author: Vitaly Buka (vitalybuka)

Changes

By default reuse can happend only after
UINT32_MAX threads, so it's almost NFC.

---

Full diff: https://github.com/llvm/llvm-project/pull/111916.diff

1 Files Affected:

• (modified) compiler-rt/lib/asan/asan_descriptions.cpp (+4-1)

diff --git a/compiler-rt/lib/asan/asan_descriptions.cpp b/compiler-rt/lib/asan/asan_descriptions.cpp
index 1c2f20a76343bb..778e134f1cf2a5 100644
--- a/compiler-rt/lib/asan/asan_descriptions.cpp
+++ b/compiler-rt/lib/asan/asan_descriptions.cpp
@@ -63,7 +63,10 @@ void DescribeThread(AsanThreadContext *context) {
   if (flags()->print_full_thread_history) {
     AsanThreadContext *parent_context =
         GetThreadContextByTidLocked(context->parent_tid);
-    DescribeThread(parent_context);
+    // `context->parent_tid` may point to reused slot, double check, `unique_id`
+    // of new user will always be greater then the child.
+    if (context->unique_id > parent_context->unique_id)
+      DescribeThread(parent_context);
   }
 }
 

[fmayer]

Do we want to print something? It might be confusing why the thread description is missing

[vitalybuka]

Do we want to print something? It might be confusing why the thread description is missing

Done