Yang Jihong

**Name of the Vulnerable Software and Affected Versions** Linux kernel (affected versions not specified) **Description** A data race has been identified between `perf event set output()` and `perf mmap close()` in the Linux kernel. This issue occurs when there is a concurrent execution of these two functions, leading to a potential deadlock situation. The problem arises because the loop in `perf mmap close()` holds the `e2->mmap mutex` lock, while the attach in `perf event set output()` holds the `e1->mmap mutex` lock, resulting in no serialization to avoid this race. This can cause a subsequent `perf mmap()` call to loop forever. **Recommendations** To alleviate this problem, it is recommended to modify the `perf event set output()` function to take both `e1->mmap mutex` and `e2->mmap mutex` locks. Additionally, the loop in `perf mmap()` should be modified to detach the `rb` directly, avoiding the need to wait for the concurrent `perf mmap close()` to complete. At the moment, there is no information about a newer version that contains a fix for this vulnerability.