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authorMing Lei <ming.lei@redhat.com>2021-08-03 15:06:08 +0800
committerJens Axboe <axboe@kernel.dk>2021-08-09 20:00:26 -0600
commit11431e26c9c43fa26f6b33ee1a90989f57b86024 (patch)
treeffa97a8ceceb46d02e715ff6fb62ed20846818ec /block/blk-iocost.c
parentfb7b9b0231ba8f77587c23f5257a4fdb6df1219e (diff)
downloadlinux-11431e26c9c43fa26f6b33ee1a90989f57b86024.tar.bz2
blk-iocost: fix lockdep warning on blkcg->lock
blkcg->lock depends on q->queue_lock which may depend on another driver lock required in irq context, one example is dm-thin: Chain exists of: &pool->lock#3 --> &q->queue_lock --> &blkcg->lock Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&blkcg->lock); local_irq_disable(); lock(&pool->lock#3); lock(&q->queue_lock); <Interrupt> lock(&pool->lock#3); Fix the issue by using spin_lock_irq(&blkcg->lock) in ioc_weight_write(). Cc: Tejun Heo <tj@kernel.org> Reported-by: Bruno Goncalves <bgoncalv@redhat.com> Link: https://lore.kernel.org/linux-block/CA+QYu4rzz6079ighEanS3Qq_Dmnczcf45ZoJoHKVLVATTo1e4Q@mail.gmail.com/T/#u Signed-off-by: Ming Lei <ming.lei@redhat.com> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20210803070608.1766400-1-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-iocost.c')
-rw-r--r--block/blk-iocost.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/block/blk-iocost.c b/block/blk-iocost.c
index 5fac3757e6e0..0e56557cacf2 100644
--- a/block/blk-iocost.c
+++ b/block/blk-iocost.c
@@ -3061,19 +3061,19 @@ static ssize_t ioc_weight_write(struct kernfs_open_file *of, char *buf,
if (v < CGROUP_WEIGHT_MIN || v > CGROUP_WEIGHT_MAX)
return -EINVAL;
- spin_lock(&blkcg->lock);
+ spin_lock_irq(&blkcg->lock);
iocc->dfl_weight = v * WEIGHT_ONE;
hlist_for_each_entry(blkg, &blkcg->blkg_list, blkcg_node) {
struct ioc_gq *iocg = blkg_to_iocg(blkg);
if (iocg) {
- spin_lock_irq(&iocg->ioc->lock);
+ spin_lock(&iocg->ioc->lock);
ioc_now(iocg->ioc, &now);
weight_updated(iocg, &now);
- spin_unlock_irq(&iocg->ioc->lock);
+ spin_unlock(&iocg->ioc->lock);
}
}
- spin_unlock(&blkcg->lock);
+ spin_unlock_irq(&blkcg->lock);
return nbytes;
}