This is a note to let you know that I've just added the patch titled
ext4: fix i_data_sem unlock order in ext4_ind_migrate()
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ext4-fix-i_data_sem-unlock-order-in-ext4_ind_migrate.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 7c3d28ee32361bdc9e6dbf86a4f89d81f7459495
Author: Artem Sadovnikov <ancowi69@xxxxxxxxx>
Date: Thu Aug 29 15:22:09 2024 +0000
ext4: fix i_data_sem unlock order in ext4_ind_migrate()
[ Upstream commit cc749e61c011c255d81b192a822db650c68b313f ]
Fuzzing reports a possible deadlock in jbd2_log_wait_commit.
This issue is triggered when an EXT4_IOC_MIGRATE ioctl is set to require
synchronous updates because the file descriptor is opened with O_SYNC.
This can lead to the jbd2_journal_stop() function calling
jbd2_might_wait_for_commit(), potentially causing a deadlock if the
EXT4_IOC_MIGRATE call races with a write(2) system call.
This problem only arises when CONFIG_PROVE_LOCKING is enabled. In this
case, the jbd2_might_wait_for_commit macro locks jbd2_handle in the
jbd2_journal_stop function while i_data_sem is locked. This triggers
lockdep because the jbd2_journal_start function might also lock the same
jbd2_handle simultaneously.
Found by Linux Verification Center (linuxtesting.org) with syzkaller.
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@xxxxxxxxx>
Co-developed-by: Mikhail Ukhin <mish.uxin2012@xxxxxxxxx>
Signed-off-by: Mikhail Ukhin <mish.uxin2012@xxxxxxxxx>
Signed-off-by: Artem Sadovnikov <ancowi69@xxxxxxxxx>
Rule: add
Link: https://lore.kernel.org/stable/20240404095000.5872-1-mish.uxin2012%40yandex.ru
Link: https://patch.msgid.link/20240829152210.2754-1-ancowi69@xxxxxxxxx
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/ext4/migrate.c b/fs/ext4/migrate.c
index b0ea646454ac8..59290356aa5b1 100644
--- a/fs/ext4/migrate.c
+++ b/fs/ext4/migrate.c
@@ -663,8 +663,8 @@ int ext4_ind_migrate(struct inode *inode)
if (unlikely(ret2 && !ret))
ret = ret2;
errout:
- ext4_journal_stop(handle);
up_write(&EXT4_I(inode)->i_data_sem);
+ ext4_journal_stop(handle);
out_unlock:
percpu_up_write(&sbi->s_writepages_rwsem);
return ret;
