diff options
| author | Xiaxi Shen <shenxiaxi26@gmail.com> | 2024-07-14 21:33:36 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-05-02 07:41:07 +0200 |
| commit | 7aac0c17a8cdf4a3236991c1e60435c6a984076c (patch) | |
| tree | c280f39026965f09128508fa5ad04e0d7626351f /fs/ext4 | |
| parent | 56a9d07f427378eeb75b917bb49c6fbea8204126 (diff) | |
ext4: fix timer use-after-free on failed mount
commit 0ce160c5bdb67081a62293028dc85758a8efb22a upstream.
Syzbot has found an ODEBUG bug in ext4_fill_super
The del_timer_sync function cancels the s_err_report timer,
which reminds about filesystem errors daily. We should
guarantee the timer is no longer active before kfree(sbi).
When filesystem mounting fails, the flow goes to failed_mount3,
where an error occurs when ext4_stop_mmpd is called, causing
a read I/O failure. This triggers the ext4_handle_error function
that ultimately re-arms the timer,
leaving the s_err_report timer active before kfree(sbi) is called.
Fix the issue by canceling the s_err_report timer after calling ext4_stop_mmpd.
Signed-off-by: Xiaxi Shen <shenxiaxi26@gmail.com>
Reported-and-tested-by: syzbot+59e0101c430934bc9a36@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=59e0101c430934bc9a36
Link: https://patch.msgid.link/20240715043336.98097-1-shenxiaxi26@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
[Minor context change fixed]
Signed-off-by: Xiangyu Chen <xiangyu.chen@windriver.com>
Signed-off-by: He Zhe <zhe.he@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/ext4')
| -rw-r--r-- | fs/ext4/super.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 1e60d957b7c1..3957ff246bff 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -5185,8 +5185,8 @@ failed_mount_wq: failed_mount3a: ext4_es_unregister_shrinker(sbi); failed_mount3: - del_timer_sync(&sbi->s_err_report); ext4_stop_mmpd(sbi); + del_timer_sync(&sbi->s_err_report); failed_mount2: rcu_read_lock(); group_desc = rcu_dereference(sbi->s_group_desc); |