diff options
| author | Tejun Heo <tj@kernel.org> | 2021-10-15 02:20:22 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-10-27 10:59:44 +0300 |
| commit | b1a34f86b41fd89441fa0e245b6b23627b0d73d3 (patch) | |
| tree | 832a3bc2394e227d38b2d16a710bc9823a6e7db0 /block | |
| parent | 152f35191d12a5a1a8dd383e97340b83494c9c97 (diff) | |
| download | linux-b1a34f86b41fd89441fa0e245b6b23627b0d73d3.tar.xz | |
blk-cgroup: blk_cgroup_bio_start() should use irq-safe operations on blkg->iostat_cpu
commit 5370b0f49078203acf3c064b634a09707167a864 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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 28e11decbac5..8e4dcf6036f6 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -1916,10 +1916,11 @@ 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 @@ -1931,7 +1932,7 @@ 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(); |