diff options
Diffstat (limited to '0119-dm-fix-race-in-dm_start_io_acct.patch')
| -rw-r--r-- | 0119-dm-fix-race-in-dm_start_io_acct.patch | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/0119-dm-fix-race-in-dm_start_io_acct.patch b/0119-dm-fix-race-in-dm_start_io_acct.patch new file mode 100644 index 000000000000..2f4af6a7c4b7 --- /dev/null +++ b/0119-dm-fix-race-in-dm_start_io_acct.patch @@ -0,0 +1,38 @@ +From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 +From: Benjamin Marzinski <bmarzins@redhat.com> +Date: Tue, 14 Jun 2022 11:10:28 -0500 +Subject: [PATCH] dm: fix race in dm_start_io_acct + +commit 10eb3a0d517fcc83eeea4242c149461205675eb4 upstream. + +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> +Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> +--- + drivers/md/dm.c | 4 ++++ + 1 file changed, 4 insertions(+) + +diff --git a/drivers/md/dm.c b/drivers/md/dm.c +index 82957bd460e894556fed5eed0b991c14f3c0713b..a68316f96350d0af64c1db865c48d1e97fbf95ca 100644 +--- a/drivers/md/dm.c ++++ b/drivers/md/dm.c +@@ -551,6 +551,10 @@ static void dm_start_io_acct(struct dm_io *io, struct bio *clone) + return; + /* 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); + } |