tree 73f6056f87cd9183e04f3b9f6a4245876cf0cb23
parent a566a6b11c86147fe9fc9db7ab15f9eecca3e862
author David Teigland <teigland@redhat.com> 1245349224 -0500
committer David Teigland <teigland@redhat.com> 1245350562 -0500

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>