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authorArtem Sadovnikov <ancowi69@gmail.com>2024-08-29 15:22:09 +0000
committerTheodore Ts'o <tytso@mit.edu>2024-09-03 22:14:17 -0400
commitcc749e61c011c255d81b192a822db650c68b313f (patch)
tree6fe2486119aae77a74f0e414cbd81110fcf1d7da /fs/ext4
parent183aa1d3baea18b199505455a0247b13de826e2f (diff)
ext4: fix i_data_sem unlock order in ext4_ind_migrate()
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@gmail.com> Co-developed-by: Mikhail Ukhin <mish.uxin2012@yandex.ru> Signed-off-by: Mikhail Ukhin <mish.uxin2012@yandex.ru> Signed-off-by: Artem Sadovnikov <ancowi69@gmail.com> Rule: add Link: https://lore.kernel.org/stable/20240404095000.5872-1-mish.uxin2012%40yandex.ru Link: https://patch.msgid.link/20240829152210.2754-1-ancowi69@gmail.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/ext4')
-rw-r--r--fs/ext4/migrate.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/ext4/migrate.c b/fs/ext4/migrate.c
index 0f68b8a14560..1b0dfd963d3f 100644
--- a/fs/ext4/migrate.c
+++ b/fs/ext4/migrate.c
@@ -664,8 +664,8 @@ 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:
ext4_writepages_up_write(inode->i_sb, alloc_ctx);
return ret;