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| author | Ming Lei <ming.lei@redhat.com> | 2022-06-16 09:44:00 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2022-06-16 14:45:15 -0600 |
| commit | 4d337cebcb1c27d9b48c48b9a98e939d4552d584 (patch) | |
| tree | 145de66b189943b28e6b089d4345459a7d22d2c6 /block/mq-deadline.c | |
| parent | 5fd7a84a09e640016fe106dd3e992f5210e23dc7 (diff) | |
| download | lwn-4d337cebcb1c27d9b48c48b9a98e939d4552d584.tar.gz lwn-4d337cebcb1c27d9b48c48b9a98e939d4552d584.zip | |
blk-mq: avoid to touch q->elevator without any protection
q->elevator is referred in blk_mq_has_sqsched() without any protection,
no .q_usage_counter is held, no queue srcu and rcu read lock is held,
so potential use-after-free may be triggered.
Fix the issue by adding one queue flag for checking if the elevator
uses single queue style dispatch. Meantime the elevator feature flag
of ELEVATOR_F_MQ_AWARE isn't needed any more.
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220616014401.817001-3-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/mq-deadline.c')
| -rw-r--r-- | block/mq-deadline.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/block/mq-deadline.c b/block/mq-deadline.c index 6ed602b2f80a..1a9e835e816c 100644 --- a/block/mq-deadline.c +++ b/block/mq-deadline.c @@ -642,6 +642,9 @@ static int dd_init_sched(struct request_queue *q, struct elevator_type *e) spin_lock_init(&dd->lock); spin_lock_init(&dd->zone_lock); + /* We dispatch from request queue wide instead of hw queue */ + blk_queue_flag_set(QUEUE_FLAG_SQ_SCHED, q); + q->elevator = eq; return 0; |