In the Linux kernel, the following vulnerability has been resolved: debugfs: fix wait/cancellation handling during remove Ben Greear further reports deadlocks during concurrent debugfs remove while files are being accessed, even though the code in question now uses debugfs cancellations. Turns out that despite all the review on the locking, we missed completely that the logic is wrong: if the refcount hits zero we can finish (and need not wait for the completion), but if it doesn’t we have to trigger all the cancellations. As written, we can never get into the loop triggering the cancellations. Fix this, and explain it better while at it.
git.kernel.org/linus/952c3fce297f12c7ff59380adb66b564e2bc9b64
git.kernel.org/stable/c/3d08cca5fd0aabb62b7015067ab40913b33da906
git.kernel.org/stable/c/952c3fce297f12c7ff59380adb66b564e2bc9b64
git.kernel.org/stable/c/e88b5ae01901c4a655a53158397746334778a57b
ubuntu.com/security/CVE-2024-35793
ubuntu.com/security/notices/USN-6816-1
ubuntu.com/security/notices/USN-6817-1
ubuntu.com/security/notices/USN-6817-2
ubuntu.com/security/notices/USN-6817-3
ubuntu.com/security/notices/USN-6878-1
www.cve.org/CVERecord?id=CVE-2024-35793