diff options
| author | Xiaxi Shen <shenxiaxi26@gmail.com> | 2024-07-14 21:33:36 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-10-10 12:00:52 +0200 |
| commit | fa78fb51d396f4f2f80f8e96a3b1516f394258be (patch) | |
| tree | 53c3e61c557fc67a508f5bb0b957c6020075acd6 /fs | |
| parent | 7633407ca4ab8be2916ab214eb44ccebc6a50e1a (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guarantee the timer is no longer active before kfree(sbi).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
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs')
| -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 edc692984404..9d8cc17d80da 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -5632,8 +5632,8 @@ failed_mount3a: failed_mount3: /* flush s_sb_upd_work before sbi destroy */ flush_work(&sbi->s_sb_upd_work); - del_timer_sync(&sbi->s_err_report); ext4_stop_mmpd(sbi); + del_timer_sync(&sbi->s_err_report); ext4_group_desc_free(sbi); failed_mount: if (sbi->s_chksum_driver) |