On Fri, Apr 21, 2017 at 04:40:21PM -0700, Bart Van Assche wrote: > One of the debugfs attributes allows to run a queue. Since running > a queue after a queue has entered the "dead" state is not allowed > and even can cause a kernel crash, unregister the debugfs attributes > before a queue reaches the "dead" state.
More important than this case, I think, is that blk_cleanup_queue() calls blk_mq_free_queue(q), so most of the debugfs entries would lead to use-after-frees. If you add that to the commit message and address my comment below, Reviewed-by: Omar Sandoval <[email protected]> > Signed-off-by: Bart Van Assche <[email protected]> > Cc: Omar Sandoval <[email protected]> > Cc: Hannes Reinecke <[email protected]> > --- > block/blk-core.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/block/blk-core.c b/block/blk-core.c > index a49b0830aaaf..33c91a4bee97 100644 > --- a/block/blk-core.c > +++ b/block/blk-core.c > @@ -566,6 +566,11 @@ void blk_cleanup_queue(struct request_queue *q) > spin_lock_irq(lock); > if (!q->mq_ops) > __blk_drain_queue(q, true); > + spin_unlock_irq(lock); > + > + blk_mq_debugfs_unregister_mq(q); > + > + spin_lock_irq(lock); > queue_flag_set(QUEUE_FLAG_DEAD, q); > spin_unlock_irq(lock); Do we actually have to hold the queue lock when we set QUEUE_FLAG_DEAD?
