blk-mq: Avoid that submitting a bio concurrently with device removal triggers a crash
Because blkcg_exit_queue() is now called from inside blk_cleanup_queue()
it is no longer safe to access cgroup information during or after the
blk_cleanup_queue() call. Hence protect the generic_make_request_checks()
call with blk_queue_enter() / blk_queue_exit().
Reported-by: Ming Lei <ming.lei@redhat.com>
Fixes: a063057d7c
("block: Fix a race between request queue removal and the block cgroup controller")
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Joseph Qi <joseph.qi@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
parent
a93f00b376
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@ -2385,8 +2385,20 @@ blk_qc_t generic_make_request(struct bio *bio)
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* yet.
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*/
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struct bio_list bio_list_on_stack[2];
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blk_mq_req_flags_t flags = 0;
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struct request_queue *q = bio->bi_disk->queue;
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blk_qc_t ret = BLK_QC_T_NONE;
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if (bio->bi_opf & REQ_NOWAIT)
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flags = BLK_MQ_REQ_NOWAIT;
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if (blk_queue_enter(q, flags) < 0) {
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if (!blk_queue_dying(q) && (bio->bi_opf & REQ_NOWAIT))
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bio_wouldblock_error(bio);
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else
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bio_io_error(bio);
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return ret;
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}
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if (!generic_make_request_checks(bio))
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goto out;
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@ -2423,11 +2435,22 @@ blk_qc_t generic_make_request(struct bio *bio)
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bio_list_init(&bio_list_on_stack[0]);
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current->bio_list = bio_list_on_stack;
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do {
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struct request_queue *q = bio->bi_disk->queue;
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blk_mq_req_flags_t flags = bio->bi_opf & REQ_NOWAIT ?
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BLK_MQ_REQ_NOWAIT : 0;
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bool enter_succeeded = true;
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if (likely(blk_queue_enter(q, flags) == 0)) {
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if (unlikely(q != bio->bi_disk->queue)) {
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if (q)
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blk_queue_exit(q);
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q = bio->bi_disk->queue;
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flags = 0;
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if (bio->bi_opf & REQ_NOWAIT)
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flags = BLK_MQ_REQ_NOWAIT;
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if (blk_queue_enter(q, flags) < 0) {
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enter_succeeded = false;
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q = NULL;
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}
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}
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if (enter_succeeded) {
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struct bio_list lower, same;
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/* Create a fresh bio_list for all subordinate requests */
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@ -2435,8 +2458,6 @@ blk_qc_t generic_make_request(struct bio *bio)
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bio_list_init(&bio_list_on_stack[0]);
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ret = q->make_request_fn(q, bio);
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blk_queue_exit(q);
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/* sort new bios into those for a lower level
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* and those for the same level
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*/
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@ -2463,6 +2484,8 @@ blk_qc_t generic_make_request(struct bio *bio)
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current->bio_list = NULL; /* deactivate */
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out:
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if (q)
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blk_queue_exit(q);
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return ret;
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}
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EXPORT_SYMBOL(generic_make_request);
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