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authorOmar Sandoval <osandov@fb.com>2020-09-08 23:46:37 +0300
committerJens Axboe <axboe@kernel.dk>2020-09-09 02:40:46 +0300
commite8a8a185051a460e3eb0617dca33f996f4e31516 (patch)
treeb04ab5361c82ca11ba54e058f160a03a910be2a3 /block
parent88ce2a530cc9865a894454b2e40eba5957a60e1a (diff)
downloadlinux-e8a8a185051a460e3eb0617dca33f996f4e31516.tar.xz
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')
-rw-r--r--block/bfq-iosched.c12
-rw-r--r--block/blk-mq-sched.h2
2 files changed, 1 insertions, 13 deletions
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index a4c0bec920cb..ee767fa000e4 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -5896,18 +5896,6 @@ static void bfq_finish_requeue_request(struct request *rq)
struct bfq_data *bfqd;
/*
- * Requeue and finish hooks are invoked in blk-mq without
- * checking whether the involved request is actually still
- * referenced in the scheduler. To handle this fact, the
- * following two checks make this function exit in case of
- * spurious invocations, for which there is nothing to do.
- *
- * First, check whether rq has nothing to do with an elevator.
- */
- if (unlikely(!(rq->rq_flags & RQF_ELVPRIV)))
- return;
-
- /*
* rq either is not associated with any icq, or is an already
* requeued request that has not (yet) been re-inserted into
* a bfq_queue.
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);
}