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authorMing Lei <ming.lei@redhat.com>2022-06-16 04:44:00 +0300
committerJens Axboe <axboe@kernel.dk>2022-06-16 23:45:15 +0300
commit4d337cebcb1c27d9b48c48b9a98e939d4552d584 (patch)
tree145de66b189943b28e6b089d4345459a7d22d2c6 /block/blk-mq-sched.c
parent5fd7a84a09e640016fe106dd3e992f5210e23dc7 (diff)
downloadlinux-4d337cebcb1c27d9b48c48b9a98e939d4552d584.tar.xz
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/blk-mq-sched.c')
-rw-r--r--block/blk-mq-sched.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
index 9e56a69422b6..eb3c65a21362 100644
--- a/block/blk-mq-sched.c
+++ b/block/blk-mq-sched.c
@@ -564,6 +564,7 @@ int blk_mq_init_sched(struct request_queue *q, struct elevator_type *e)
int ret;
if (!e) {
+ blk_queue_flag_clear(QUEUE_FLAG_SQ_SCHED, q);
q->elevator = NULL;
q->nr_requests = q->tag_set->queue_depth;
return 0;