diff options
| author | Benjamin Marzinski <bmarzins@redhat.com> | 2022-06-14 11:10:28 -0500 |
|---|---|---|
| committer | Mike Snitzer <snitzer@kernel.org> | 2022-06-15 11:51:41 -0400 |
| commit | 10eb3a0d517fcc83eeea4242c149461205675eb4 (patch) | |
| tree | c1a72661ab3a31ea4c6155918bbb979ebbec522f | |
| parent | b13baccc3850ca8b8cccbf8ed9912dbaa0fdf7f3 (diff) | |
| download | linux-10eb3a0d517fcc83eeea4242c149461205675eb4.tar.bz2 | |
dm: fix race in dm_start_io_acct
After commit 82f6cdcc3676c ("dm: switch dm_io booleans over to proper
flags") dm_start_io_acct stopped atomically checking and setting
was_accounted, which turned into the DM_IO_ACCOUNTED flag. This opened
the possibility for a race where IO accounting is started twice for
duplicate bios. To remove the race, check the flag while holding the
io->lock.
Fixes: 82f6cdcc3676c ("dm: switch dm_io booleans over to proper flags")
Cc: stable@vger.kernel.org
Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
| -rw-r--r-- | drivers/md/dm.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c index d8f16183bf27..d5e6d33700e5 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -555,6 +555,10 @@ static void dm_start_io_acct(struct dm_io *io, struct bio *clone) unsigned long flags; /* Can afford locking given DM_TIO_IS_DUPLICATE_BIO */ spin_lock_irqsave(&io->lock, flags); + if (dm_io_flagged(io, DM_IO_ACCOUNTED)) { + spin_unlock_irqrestore(&io->lock, flags); + return; + } dm_io_set_flag(io, DM_IO_ACCOUNTED); spin_unlock_irqrestore(&io->lock, flags); } |