Messages in this thread Patch in this message | | | From | Bart Van Assche <> | Subject | [PATCH v7 21/23] block: Avoid that flushing triggers a lockdep complaint | Date | Thu, 14 Feb 2019 15:00:56 -0800 |
| |
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: Jens Axboe <axboe@kernel.dk> Cc: Ming Lei <ming.lei@redhat.com> Cc: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Bart Van Assche <bvanassche@acm.org> --- block/blk-flush.c | 5 ++++- block/blk.h | 1 + 2 files changed, 5 insertions(+), 1 deletion(-)
diff --git a/block/blk-flush.c b/block/blk-flush.c index 6e0f2d97fc6d..86c86c76c087 100644 --- a/block/blk-flush.c +++ b/block/blk-flush.c @@ -70,6 +70,7 @@ #include <linux/blkdev.h> #include <linux/gfp.h> #include <linux/blk-mq.h> +#include <linux/lockdep.h> #include "blk.h" #include "blk-mq.h" @@ -472,7 +473,8 @@ struct blk_flush_queue *blk_alloc_flush_queue(struct request_queue *q, if (!fq) goto fail; - spin_lock_init(&fq->mq_flush_lock); + lockdep_register_key(&fq->key); + spin_lock_init_key(&fq->mq_flush_lock, &fq->key); rq_sz = round_up(rq_sz + cmd_size, cache_line_size()); fq->flush_rq = kzalloc_node(rq_sz, flags, node); @@ -497,6 +499,7 @@ 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 848278c52030..10f5e19aa4a1 100644 --- a/block/blk.h +++ b/block/blk.h @@ -28,6 +28,7 @@ struct blk_flush_queue { * at the same time */ struct request *orig_rq; + struct lock_class_key key; spinlock_t mq_flush_lock; }; -- 2.21.0.rc0.258.g878e2cd30e-goog
| |