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| author | Omar Sandoval <osandov@fb.com> | 2020-09-08 13:46:37 -0700 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2020-09-08 17:40:46 -0600 |
| commit | e8a8a185051a460e3eb0617dca33f996f4e31516 (patch) | |
| tree | b04ab5361c82ca11ba54e058f160a03a910be2a3 /block/blk-mq-sched.h | |
| parent | 88ce2a530cc9865a894454b2e40eba5957a60e1a (diff) | |
| download | lwn-e8a8a185051a460e3eb0617dca33f996f4e31516.tar.gz lwn-e8a8a185051a460e3eb0617dca33f996f4e31516.zip | |
block: only call sched requeue_request() for scheduled requests
Yang Yang reported the following crash caused by requeueing a flush
request in Kyber:
[ 2.517297] Unable to handle kernel paging request at virtual address ffffffd8071c0b00
...
[ 2.517468] pc : clear_bit+0x18/0x2c
[ 2.517502] lr : sbitmap_queue_clear+0x40/0x228
[ 2.517503] sp : ffffff800832bc60 pstate : 00c00145
...
[ 2.517599] Process ksoftirqd/5 (pid: 51, stack limit = 0xffffff8008328000)
[ 2.517602] Call trace:
[ 2.517606] clear_bit+0x18/0x2c
[ 2.517619] kyber_finish_request+0x74/0x80
[ 2.517627] blk_mq_requeue_request+0x3c/0xc0
[ 2.517637] __scsi_queue_insert+0x11c/0x148
[ 2.517640] scsi_softirq_done+0x114/0x130
[ 2.517643] blk_done_softirq+0x7c/0xb0
[ 2.517651] __do_softirq+0x208/0x3bc
[ 2.517657] run_ksoftirqd+0x34/0x60
[ 2.517663] smpboot_thread_fn+0x1c4/0x2c0
[ 2.517667] kthread+0x110/0x120
[ 2.517669] ret_from_fork+0x10/0x18
This happens because Kyber doesn't track flush requests, so
kyber_finish_request() reads a garbage domain token. Only call the
scheduler's requeue_request() hook if RQF_ELVPRIV is set (like we do for
the finish_request() hook in blk_mq_free_request()). Now that we're
handling it in blk-mq, also remove the check from BFQ.
Reported-by: Yang Yang <yang.yang@vivo.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-mq-sched.h')
| -rw-r--r-- | block/blk-mq-sched.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/block/blk-mq-sched.h b/block/blk-mq-sched.h index 126021fc3a11..e81ca1bf6e10 100644 --- a/block/blk-mq-sched.h +++ b/block/blk-mq-sched.h @@ -66,7 +66,7 @@ static inline void blk_mq_sched_requeue_request(struct request *rq) struct request_queue *q = rq->q; struct elevator_queue *e = q->elevator; - if (e && e->type->ops.requeue_request) + if ((rq->rq_flags & RQF_ELVPRIV) && e && e->type->ops.requeue_request) e->type->ops.requeue_request(rq); } |