IB/uverbs: Protect QP multicast list
Userspace verbs multicast attach/detach operations on a QP are done
while holding the rwsem of the QP for reading. That's not sufficient
since a reader lock allows more than one reader to acquire the
lock. However, multicast attach/detach does list manipulation that
can corrupt the list if multiple threads run in parallel.
Fix this by acquiring the rwsem as a writer to serialize attach/detach
operations. Add idr_write_qp() and put_qp_write() to encapsulate
this.
This fixes oops seen when running applications that perform multicast
joins/leaves.
Reported by: Mike Dubman <miked@mellanox.com>
Signed-off-by: Eli Cohen <eli@mellanox.com>
Cc: <stable@kernel.org>
Signed-off-by: Roland Dreier <roland@purestorage.com>
1 file changed