CVE-2024-35793

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.