Re: [PATCH] ocfs2: validate truncate log dinode before caching

[Joseph Qi]

On 7/23/26 11:05 AM, ZhengYuan Huang wrote:
> On Wed, Jul 22, 2026 at 8:56 PM Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx> wrote:
>>
>>
>>
>> On 7/22/26 5:11 PM, ZhengYuan Huang wrote:
>>> [BUG]
>>> A corrupted truncate log dinode can pass through mount initialization and
>>> reach the delayed flush worker, where it triggers:
>>>
>>> kernel BUG at fs/ocfs2/alloc.c:6019!
>>> Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
>>> RIP: 0010:__ocfs2_flush_truncate_log+0xa87/0xf10 fs/ocfs2/alloc.c:6019
>>> Call Trace:
>>>  ocfs2_flush_truncate_log fs/ocfs2/alloc.c:6084 [inline]
>>>  ocfs2_truncate_log_worker+0xa9/0x180 fs/ocfs2/alloc.c:6097
>>>  process_one_work+0x8e0/0x1980 kernel/workqueue.c:3263
>>>  ...
>>>
>>
>> I've encountered this BUG occasionality. But I don't see why it happens.
>> Do you have more clues on how to reproduce it?
>>
>> Thanks,
>> Joseph
> 
> Thanks for looking into this.
> 
> This bug was originally found by our fuzzing tool. We tried to
> reproduce it using the automatically saved disk image and syscall
> program, but so far we have been unable to reproduce the BUG in
> __ocfs2_flush_truncate_log directly. Instead, the same artifacts have
> triggered two other issues:
> 
> KASAN: use-after-free Read in ocfs2_dx_dir_search
> kernel BUG in ocfs2_grow_tree
> 
> For the use-after-free in ocfs2_dx_dir_search, I previously submitted
> a patch that addresses what I believe is its root cause:
> 
> https://lore.kernel.org/all/20260416082105.1295887-1-gality369@xxxxxxxxx/
> 
> However, I have not received any feedback on the patch yet, and at
> this point we are not sure whether that issue is related to the
> truncate-log corruption reported here.
> 

It seems I've missed the thread.

And I've found a similar one in:
https://lore.kernel.org/ocfs2-devel/20260713205625.92391-1-doruk@xxxxxxx/

Could you please check if it fixes the same issue?

Thanks,
Joseph

> We are continuing to investigate and will share any new findings. In
> the meantime, the original artifacts generated by our fuzzer are
> available here:
> 
> https://drive.google.com/file/d/1zCJoUb2uwVqTrGIM4JFLbwkcHRz04TJo/view?usp=sharing
> 
> The archive contains the disk image, the PoC program, and a kernel
> log. To run the reproducer, mount the supplied disk image and execute
> the PoC. Please note that, in our current tests, these artifacts can
> trigger the two issues mentioned above, but they do not reproduce the
> BUG in __ocfs2_flush_truncate_log. The archive also includes the
> kernel log captured when the original BUG occurred, which may help
> with further investigation.
> 
> Thanks,
> ZhengYuan Huang