| Message ID | YWi7NrQdVlxD6J9W@slm.duckdns.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [block-5.15] blk-cgroup: blk_cgroup_bio_start() should use irq-safe operations on blkg->iostat_cpu | expand |
On Thu, 14 Oct 2021 13:20:22 -1000, Tejun Heo wrote: > 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. > > Applied, thanks! [1/1] blk-cgroup: blk_cgroup_bio_start() should use irq-safe operations on blkg->iostat_cpu commit: 5370b0f49078203acf3c064b634a09707167a864 Best regards,
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index 31fe9be179d99..7d0509d9f4ea8 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -1906,10 +1906,11 @@ 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 @@ -1921,7 +1922,7 @@ 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();
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> --- block/blk-cgroup.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)