![Omar Sandoval](/assets/img/avatar_default.png)
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>
89 lines
2.5 KiB
C
89 lines
2.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef BLK_MQ_SCHED_H
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#define BLK_MQ_SCHED_H
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#include "blk-mq.h"
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#include "blk-mq-tag.h"
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void blk_mq_sched_free_hctx_data(struct request_queue *q,
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void (*exit)(struct blk_mq_hw_ctx *));
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void blk_mq_sched_assign_ioc(struct request *rq);
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void blk_mq_sched_request_inserted(struct request *rq);
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bool blk_mq_sched_try_merge(struct request_queue *q, struct bio *bio,
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unsigned int nr_segs, struct request **merged_request);
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bool __blk_mq_sched_bio_merge(struct request_queue *q, struct bio *bio,
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unsigned int nr_segs);
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bool blk_mq_sched_try_insert_merge(struct request_queue *q, struct request *rq);
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void blk_mq_sched_mark_restart_hctx(struct blk_mq_hw_ctx *hctx);
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void blk_mq_sched_restart(struct blk_mq_hw_ctx *hctx);
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void blk_mq_sched_insert_request(struct request *rq, bool at_head,
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bool run_queue, bool async);
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void blk_mq_sched_insert_requests(struct blk_mq_hw_ctx *hctx,
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struct blk_mq_ctx *ctx,
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struct list_head *list, bool run_queue_async);
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void blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx);
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int blk_mq_init_sched(struct request_queue *q, struct elevator_type *e);
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void blk_mq_exit_sched(struct request_queue *q, struct elevator_queue *e);
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void blk_mq_sched_free_requests(struct request_queue *q);
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static inline bool
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blk_mq_sched_bio_merge(struct request_queue *q, struct bio *bio,
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unsigned int nr_segs)
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{
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if (blk_queue_nomerges(q) || !bio_mergeable(bio))
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return false;
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return __blk_mq_sched_bio_merge(q, bio, nr_segs);
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}
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static inline bool
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blk_mq_sched_allow_merge(struct request_queue *q, struct request *rq,
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struct bio *bio)
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{
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struct elevator_queue *e = q->elevator;
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if (e && e->type->ops.allow_merge)
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return e->type->ops.allow_merge(q, rq, bio);
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return true;
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}
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static inline void blk_mq_sched_completed_request(struct request *rq, u64 now)
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{
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struct elevator_queue *e = rq->q->elevator;
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if (e && e->type->ops.completed_request)
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e->type->ops.completed_request(rq, now);
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}
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static inline void blk_mq_sched_requeue_request(struct request *rq)
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{
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struct request_queue *q = rq->q;
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struct elevator_queue *e = q->elevator;
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if ((rq->rq_flags & RQF_ELVPRIV) && e && e->type->ops.requeue_request)
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e->type->ops.requeue_request(rq);
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}
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static inline bool blk_mq_sched_has_work(struct blk_mq_hw_ctx *hctx)
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{
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struct elevator_queue *e = hctx->queue->elevator;
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if (e && e->type->ops.has_work)
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return e->type->ops.has_work(hctx);
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return false;
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}
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static inline bool blk_mq_sched_needs_restart(struct blk_mq_hw_ctx *hctx)
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{
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return test_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state);
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}
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#endif
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