published October 4, 2025
In the Linux kernel, the following vulnerability has been resolved:
ocfs2: fix defrag path triggering jbd2 ASSERT
code path:
ocfs2_ioctl_move_extents
ocfs2_move_extents
ocfs2_defrag_extent
__ocfs2_move_extent
+ ocfs2_journal_access_di
+ ocfs2_split_extent //sub-paths call jbd2_journal_restart
+ ocfs2_journal_dirty //crash by jbs2 ASSERT
crash stacks:
PID: 11297 TASK: ffff974a676dcd00 CPU: 67 COMMAND: "defragfs.ocfs2"
#0 [ffffb25d8dad3900] machine_kexec at ffffffff8386fe01
#1 [ffffb25d8dad3958] __crash_kexec at ffffffff8395959d
#2 [ffffb25d8dad3a20] crash_kexec at ffffffff8395a45d
#3 [ffffb25d8dad3a38] oops_end at ffffffff83836d3f
#4 [ffffb25d8dad3a58] do_trap at ffffffff83833205
#5 [ffffb25d8dad3aa0] do_invalid_op at ffffffff83833aa6
#6 [ffffb25d8dad3ac0] invalid_op at ffffffff84200d18
[exception RIP: jbd2_journal_dirty_metadata+0x2ba]
RIP: ffffffffc09ca54a RSP: ffffb25d8dad3b70 RFLAGS: 00010207
RAX: 0000000000000000 RBX: ffff9706eedc5248 RCX: 0000000000000000
RDX: 0000000000000001 RSI: ffff97337029ea28 RDI: ffff9706eedc5250
RBP: ffff9703c3520200 R8: 000000000f46b0b2 R9: 0000000000000000
R10: 0000000000000001 R11: 00000001000000fe R12: ffff97337029ea28
R13: 0000000000000000 R14: ffff9703de59bf60 R15: ffff9706eedc5250
ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018
#7 [ffffb25d8dad3ba8] ocfs2_journal_dirty at ffffffffc137fb95 [ocfs2]
#8 [ffffb25d8dad3be8] __ocfs2_move_extent at ffffffffc139a950 [ocfs2]
#9 [ffffb25d8dad3c80] ocfs2_defrag_extent at ffffffffc139b2d2 [ocfs2]
Analysis
This bug has the same root cause of 'commit 7f27ec978b0e ("ocfs2: call
ocfs2_journal_access_di() before ocfs2_journal_dirty() in
ocfs2_write_end_nolock()")'. For this bug, jbd2_journal_restart() is
called by ocfs2_split_extent() during defragmenting.
How to fix
For ocfs2_split_extent() can handle journal operations totally by itself.
Caller doesn't need to call journal access/dirty pair, and caller only
needs to call journal start/stop pair. The fix method is to remove
journal access/dirty from __ocfs2_move_extent().
The discussion for this patch:
https://oss.oracle.com/pipermail/ocfs2-devel/2023-February/000647.html