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.