diff options
| author | Tejun Heo <tj@kernel.org> | 2021-10-14 13:20:22 -1000 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2021-10-17 10:40:10 -0600 |
| commit | 5370b0f49078203acf3c064b634a09707167a864 (patch) | |
| tree | 5ae81744cf93a34777e836a7fc4680b25c162002 /block | |
| parent | d29bd41428cfff9b582c248db14a47e2be8457a8 (diff) | |
| download | lwn-5370b0f49078203acf3c064b634a09707167a864.tar.gz lwn-5370b0f49078203acf3c064b634a09707167a864.zip | |
blk-cgroup: blk_cgroup_bio_start() should use irq-safe operations on blkg->iostat_cpu
c3df5fb57fe8 ("cgroup: rstat: fix A-A deadlock on 32bit around
u64_stats_sync") made u64_stats updates irq-safe to avoid A-A deadlocks.
Unfortunately, the conversion missed one in blk_cgroup_bio_start(). Fix it.
Fixes: 2d146aa3aa84 ("mm: memcontrol: switch to rstat")
Cc: stable@vger.kernel.org # v5.13+
Reported-by: syzbot+9738c8815b375ce482a1@syzkaller.appspotmail.com
Signed-off-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/YWi7NrQdVlxD6J9W@slm.duckdns.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
| -rw-r--r-- | block/blk-cgroup.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index 38b9f7684952..9a1c5839dd46 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -1897,10 +1897,11 @@ void blk_cgroup_bio_start(struct bio *bio) { int rwd = blk_cgroup_io_type(bio), cpu; struct blkg_iostat_set *bis; + unsigned long flags; cpu = get_cpu(); bis = per_cpu_ptr(bio->bi_blkg->iostat_cpu, cpu); - u64_stats_update_begin(&bis->sync); + flags = u64_stats_update_begin_irqsave(&bis->sync); /* * If the bio is flagged with BIO_CGROUP_ACCT it means this is a split @@ -1912,7 +1913,7 @@ void blk_cgroup_bio_start(struct bio *bio) } bis->cur.ios[rwd]++; - u64_stats_update_end(&bis->sync); + u64_stats_update_end_irqrestore(&bis->sync, flags); if (cgroup_subsys_on_dfl(io_cgrp_subsys)) cgroup_rstat_updated(bio->bi_blkg->blkcg->css.cgroup, cpu); put_cpu(); |