Re: [PATCH] jfs: fix shift-out-of-bounds in dbJoin

Dave Kleikamp
2024-01-29T21:17:41Z

On 1/29/24 12:29PM, Matthew Wilcox wrote:
> On Mon, Jan 29, 2024 at 09:00:56AM -0600, Dave Kleikamp wrote:
>> On 1/29/24 8:55AM, Matthew Wilcox wrote:
>>> On Mon, Jan 29, 2024 at 08:39:18AM -0600, Dave Kleikamp wrote:
>>>> On 1/28/24 2:49PM, Matthew Wilcox wrote:
>>>>> On Wed, Oct 11, 2023 at 08:09:37PM +0530, Manas Ghandat wrote:
>>>>>> Currently while joining the leaf in a buddy system there is shift out
>>>>>> of bound error in calculation of BUDSIZE. Added the required check
>>>>>> to the BUDSIZE and fixed the documentation as well.
>>>>>
>>>>> This patch causes xfstests to fail frequently. The one this trace is
>>>>> from was generic/074.
>>>>
>>>> Thanks for catching this. The sanity test is not right, so we need to revert
>>>> that one.
>>>
>>> Unfortunately, my overnight test run with this patch reverted crashed
>>> again with the same signature. I also reverted the parent commit,
>>> and when that crashed I also reverted the parent of that. Which also
>>> crashed.
>>>
>>> So maybe there's something else that makes this unstable. Or maybe my
>>> bisect went wrong. Or _something_. Anyway, I'm going to spend much of
>>> today hammering on generic/074 with various kernel versions and see what
>>> I can deduce.
>>>
>>> So far I see no evidence that v6.7 crashes with g/074. And I know that
>>> next-20240125 does crash with g/074. I'm pretty sure that v6.8-rc1 also
>>> crashes with g/074, but will confirm that.
>>
>> I'll try to beat on it too and see what I find.
>>
>> Sasha, maybe hold up on to all the jfs patches for the time being.
>
> I have it reproducing easily on cca974daeb6c. I ran it a lot on
> e0e1958f4c36 and have not reproduced it. So I'm going back to my
> earlier assertion that cca974daeb6c is bad. Now, maybe other commits
> are also bad?

I was able to reproduce it too, but not after reverting that one. I
believe it is the only one causing problems.

I only asked Sasha to hold the other ones as a precaution until we were
more confident that this one was the problem.

Shaggy