Re: [regression] Bug 216932 - io_uring with libvirt cause kernel NULL pointer dereference since 6.1.5

[Jens Axboe]

On 1/16/23 7:49 AM, Greg Kroah-Hartman wrote:
> On Mon, Jan 16, 2023 at 07:13:40AM -0700, Jens Axboe wrote:
>> On 1/16/23 6:42 AM, Jens Axboe wrote:
>>> On 1/16/23 6:17?AM, Linux kernel regression tracking (Thorsten Leemhuis) wrote:
>>>> Hi, this is your Linux kernel regression tracker.
>>>>
>>>> I noticed a regression report in bugzilla.kernel.org. As many (most?)
>>>> kernel developer don't keep an eye on it, I decided to forward it by
>>>> mail. Quoting from https://bugzilla.kernel.org/show_bug.cgi?id=216932 :
>>>
>>> Looks like:
>>>
>>> commit 6d47e0f6a535701134d950db65eb8fe1edf0b575
>>> Author: Jens Axboe <axboe@xxxxxxxxx>
>>> Date:   Wed Jan 4 08:52:06 2023 -0700
>>>
>>>     block: don't allow splitting of a REQ_NOWAIT bio
>>>
>>> got picked up by stable, but not the required prep patch:
>>>
>>>
>>> commit 613b14884b8595e20b9fac4126bf627313827fbe
>>> Author: Jens Axboe <axboe@xxxxxxxxx>
>>> Date:   Wed Jan 4 08:51:19 2023 -0700
>>>
>>>     block: handle bio_split_to_limits() NULL return
>>>
>>> Greg/team, can you pick the latter too? It'll pick cleanly for
>>> 6.1-stable, not sure how far back the other patch has gone yet.
>>
>> Looked back, and 5.15 has it too, but the cherry-pick won't work
>> on that kernel.
>>
>> Here's one for 5.15-stable that I verified crashes before this one,
>> and works with it. Haven't done an allmodconfig yet...
> 
> All now queued up, thanks!

Thanks Greg! This one was my fault, as it was a set of 2 patches and
I only marked 2/2 for stable. But how is that best handled? 1/2 could've
been marked stable as well, but I don't think that would have prevented
2/2 applying fine and 1/2 failing and hence not getting queued up until
I would've done a backport.

What's the recommended way to describe the dependency that you only
want 2/2 applied when 1/2 is in as well?

-- 
Jens Axboe