dlm: fix plock use-after-free
Fix a regression from the original addition of nfs lock support
586759f03e2e9031ac5589912a51a909ed53c30a. When a synchronous
(non-nfs) plock completes, the waiting thread will wake up and
free the op struct. This races with the user thread in
dev_write() which goes on to read the op's callback field to
check if the lock is async and needs a callback. This check
can happen on the freed op. The fix is to note the callback
value before the op can be freed.
Signed-off-by: David Teigland <teigland@redhat.com>
1 file changed