[Lldb-commits] [lldb] [lldb] Fix use-after-free in SBMutexTest (PR #133840)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-lldb

Author: Jonas Devlieghere (JDevlieghere)

<details>
<summary>Changes</summary>

The `locked` variable can be accessed from the asynchronous thread until the call to f.wait() completes. However, the variable is scoped in a lexical block that ends before that, leading to a use-after-free.

---
Full diff: https://github.com/llvm/llvm-project/pull/133840.diff


1 Files Affected:

- (modified) lldb/unittests/API/SBMutexTest.cpp (+1-2) 


``````````diff
diff --git a/lldb/unittests/API/SBMutexTest.cpp b/lldb/unittests/API/SBMutexTest.cpp
index 0b888c2725aa9..aafad59d58c17 100644
--- a/lldb/unittests/API/SBMutexTest.cpp
+++ b/lldb/unittests/API/SBMutexTest.cpp
@@ -32,10 +32,9 @@ class SBMutexTest : public testing::Test {
 
 TEST_F(SBMutexTest, LockTest) {
   lldb::SBTarget target = debugger.GetDummyTarget();
-
+  std::atomic<bool> locked = false;
   std::future<void> f;
   {
-    std::atomic<bool> locked = false;
     lldb::SBMutex lock = target.GetAPIMutex();
     std::lock_guard<lldb::SBMutex> lock_guard(lock);
     ASSERT_FALSE(locked.exchange(true));

``````````

</details>


https://github.com/llvm/llvm-project/pull/133840