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| author | Artem Sadovnikov <ancowi69@gmail.com> | 2024-08-29 18:22:09 +0300 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2024-09-04 05:14:17 +0300 |
| commit | cc749e61c011c255d81b192a822db650c68b313f (patch) | |
| tree | 6fe2486119aae77a74f0e414cbd81110fcf1d7da /fs/ext4 | |
| parent | 183aa1d3baea18b199505455a0247b13de826e2f (diff) | |
| download | linux-cc749e61c011c255d81b192a822db650c68b313f.tar.xz | |
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.c | 2 |
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; |