From: Mike Snitzer snitzer@redhat.com
stable inclusion from stable-v5.10.115 commit 7676a5b99f3da170d42d3e457cd7ff8c82001dd1 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I5IZ9C
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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commit 9f6dc633761006f974701d4c88da71ab68670749 upstream.
Commit d208b89401e0 ("dm: fix mempool NULL pointer race when completing IO") didn't go far enough.
When bio_end_io_acct ends the count of in-flight I/Os may reach zero and the DM device may be suspended. There is a possibility that the suspend races with dm_stats_account_io.
Fix this by adding percpu "pending_io" counters to track outstanding dm_io. Move kicking of suspend queue to dm_io_dec_pending(). Also, rename md_in_flight_bios() to dm_in_flight_bios() and update it to iterate all pending_io counters.
Fixes: d208b89401e0 ("dm: fix mempool NULL pointer race when completing IO") Cc: stable@vger.kernel.org Co-developed-by: Mikulas Patocka mpatocka@redhat.com Signed-off-by: Mikulas Patocka mpatocka@redhat.com Signed-off-by: Mike Snitzer snitzer@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com Acked-by: Xie XiuQi xiexiuqi@huawei.com --- drivers/md/dm.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/md/dm.c b/drivers/md/dm.c index f1db4a9d1dff..588e8b43efab 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -599,13 +599,15 @@ static void end_io_acct(struct mapped_device *md, struct bio *bio, { unsigned long duration = jiffies - start_time;
- bio_end_io_acct(bio, start_time); - if (unlikely(dm_stats_used(&md->stats))) dm_stats_account_io(&md->stats, bio_data_dir(bio), bio->bi_iter.bi_sector, bio_sectors(bio), true, duration, stats_aux);
+ smp_wmb(); + + bio_end_io_acct(bio, start_time); + /* nudge anyone waiting on suspend queue */ if (unlikely(wq_has_sleeper(&md->wait))) wake_up(&md->wait); @@ -2330,6 +2332,8 @@ static int dm_wait_for_bios_completion(struct mapped_device *md, long task_state } finish_wait(&md->wait, &wait);
+ smp_rmb(); + return r; }