mirrors
/
linux-stable
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
1
0
Fork 0
Code Issues Releases Wiki Activity

dm: interlock pending dm_io and dm_wait_for_bios_completion 

commit 9f6dc63376 upstream.

Commit d208b89401 ("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: d208b89401 ("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: Mikulas Patocka <mpatocka@redhat.com>
Reviewed-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Mike Snitzer 2022-02-17 23:40:02 -05:00 committed by Greg Kroah-Hartman
parent d35aef9c60
commit c3cd91f822
1 changed files with 2 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/md/dm.c
View File

@ -2230,6 +2230,8 @@ static int dm_wait_for_completion(struct mapped_device *md, long task_state)
}
finish_wait(&md->wait, &wait);
smp_rmb(); /* paired with atomic_dec_return in end_io_acct */
return r;
}