diff options
| author | Ming Lei <ming.lei@redhat.com> | 2021-06-09 09:30:46 +0300 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2021-06-18 17:50:13 +0300 |
| commit | f0c1c4d2864ed614f90d2da1bab1a1c42907b940 (patch) | |
| tree | 85839bf9a39f116ce20217df43d358ad4571e41c /block/blk-mq-sched.c | |
| parent | 828615950b5876e75587fdd5e9d1185be9cabba7 (diff) | |
| download | linux-f0c1c4d2864ed614f90d2da1bab1a1c42907b940.tar.xz | |
blk-mq: fix use-after-free in blk_mq_exit_sched
tagset can't be used after blk_cleanup_queue() is returned because
freeing tagset usually follows blk_clenup_queue(). Commit d97e594c5166
("blk-mq: Use request queue-wide tags for tagset-wide sbitmap") adds
check on q->tag_set->flags in blk_mq_exit_sched(), and causes
use-after-free.
Fixes it by using hctx->flags.
Reported-by: syzbot+77ba3d171a25c56756ea@syzkaller.appspotmail.com
Fixes: d97e594c5166 ("blk-mq: Use request queue-wide tags for tagset-wide sbitmap")
Cc: John Garry <john.garry@huawei.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Tested-by: John Garry <john.garry@huawei.com>
Reviewed-by: John Garry <john.garry@huawei.com>
Link: https://lore.kernel.org/r/20210609063046.122843-1-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.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c index a9182d2f8ad3..80273245d11a 100644 --- a/block/blk-mq-sched.c +++ b/block/blk-mq-sched.c @@ -680,6 +680,7 @@ void blk_mq_exit_sched(struct request_queue *q, struct elevator_queue *e) { struct blk_mq_hw_ctx *hctx; unsigned int i; + unsigned int flags = 0; queue_for_each_hw_ctx(q, hctx, i) { blk_mq_debugfs_unregister_sched_hctx(hctx); @@ -687,12 +688,13 @@ void blk_mq_exit_sched(struct request_queue *q, struct elevator_queue *e) e->type->ops.exit_hctx(hctx, i); hctx->sched_data = NULL; } + flags = hctx->flags; } blk_mq_debugfs_unregister_sched(q); if (e->type->ops.exit_sched) e->type->ops.exit_sched(e); blk_mq_sched_tags_teardown(q); - if (blk_mq_is_sbitmap_shared(q->tag_set->flags)) + if (blk_mq_is_sbitmap_shared(flags)) blk_mq_exit_sched_shared_sbitmap(q); q->elevator = NULL; } |