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| author | Bart Van Assche <bvanassche@acm.org> | 2019-12-17 16:24:35 -0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2019-12-20 11:52:01 -0700 |
| commit | b3c6a59975415bde29cfd76ff1ab008edbf614a9 (patch) | |
| tree | 9aa79af93a2eabcb3acd5f9fad925e5d54e36b21 /block | |
| parent | c44a4edb20938c85b64a256661443039f5bffdea (diff) | |
| download | linux-b3c6a59975415bde29cfd76ff1ab008edbf614a9.tar.gz linux-b3c6a59975415bde29cfd76ff1ab008edbf614a9.tar.bz2 linux-b3c6a59975415bde29cfd76ff1ab008edbf614a9.zip | |
block: Fix a lockdep complaint triggered by request queue flushing
Avoid that running test nvme/012 from the blktests suite triggers the
following false positive lockdep complaint:
============================================
WARNING: possible recursive locking detected
5.0.0-rc3-xfstests-00015-g1236f7d60242 #841 Not tainted
--------------------------------------------
ksoftirqd/1/16 is trying to acquire lock:
000000000282032e (&(&fq->mq_flush_lock)->rlock){..-.}, at: flush_end_io+0x4e/0x1d0
but task is already holding lock:
00000000cbadcbc2 (&(&fq->mq_flush_lock)->rlock){..-.}, at: flush_end_io+0x4e/0x1d0
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(&(&fq->mq_flush_lock)->rlock);
lock(&(&fq->mq_flush_lock)->rlock);
*** DEADLOCK ***
May be due to missing lock nesting notation
1 lock held by ksoftirqd/1/16:
#0: 00000000cbadcbc2 (&(&fq->mq_flush_lock)->rlock){..-.}, at: flush_end_io+0x4e/0x1d0
stack backtrace:
CPU: 1 PID: 16 Comm: ksoftirqd/1 Not tainted 5.0.0-rc3-xfstests-00015-g1236f7d60242 #841
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
dump_stack+0x67/0x90
__lock_acquire.cold.45+0x2b4/0x313
lock_acquire+0x98/0x160
_raw_spin_lock_irqsave+0x3b/0x80
flush_end_io+0x4e/0x1d0
blk_mq_complete_request+0x76/0x110
nvmet_req_complete+0x15/0x110 [nvmet]
nvmet_bio_done+0x27/0x50 [nvmet]
blk_update_request+0xd7/0x2d0
blk_mq_end_request+0x1a/0x100
blk_flush_complete_seq+0xe5/0x350
flush_end_io+0x12f/0x1d0
blk_done_softirq+0x9f/0xd0
__do_softirq+0xca/0x440
run_ksoftirqd+0x24/0x50
smpboot_thread_fn+0x113/0x1e0
kthread+0x121/0x140
ret_from_fork+0x3a/0x50
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Hannes Reinecke <hare@suse.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
| -rw-r--r-- | block/blk-flush.c | 5 | ||||
| -rw-r--r-- | block/blk.h | 1 |
2 files changed, 6 insertions, 0 deletions
diff --git a/block/blk-flush.c b/block/blk-flush.c index 1777346baf06..3f977c517960 100644 --- a/block/blk-flush.c +++ b/block/blk-flush.c @@ -69,6 +69,7 @@ #include <linux/blkdev.h> #include <linux/gfp.h> #include <linux/blk-mq.h> +#include <linux/lockdep.h> #include "blk.h" #include "blk-mq.h" @@ -505,6 +506,9 @@ struct blk_flush_queue *blk_alloc_flush_queue(struct request_queue *q, INIT_LIST_HEAD(&fq->flush_queue[1]); INIT_LIST_HEAD(&fq->flush_data_in_flight); + lockdep_register_key(&fq->key); + lockdep_set_class(&fq->mq_flush_lock, &fq->key); + return fq; fail_rq: @@ -519,6 +523,7 @@ void blk_free_flush_queue(struct blk_flush_queue *fq) if (!fq) return; + lockdep_unregister_key(&fq->key); kfree(fq->flush_rq); kfree(fq); } diff --git a/block/blk.h b/block/blk.h index 6842f28c033e..0b8884353f6b 100644 --- a/block/blk.h +++ b/block/blk.h @@ -30,6 +30,7 @@ struct blk_flush_queue { * at the same time */ struct request *orig_rq; + struct lock_class_key key; spinlock_t mq_flush_lock; }; |