Re: [GIT PULL for-6.3] Block updates for 6.3

[Jens Axboe <axboe@kernel.dk>]

On 2/20/23 3:52 PM, Linus Torvalds wrote:
> On Thu, Feb 16, 2023 at 6:54 PM Jens Axboe <axboe@kernel.dk> wrote:
>>
>> I've pushed a merged branch here:
>>
>> https://git.kernel.dk/cgit/linux-block/log/?h=for-6.3/block-merged
> 
> Hmm. I do verify against suggested merges after doing my own (even
> when your suggested merge was then made stale by another later
> addition), and I think your merge was wrong wrt bfq_sync_bfqq_move(),
> which in your version does the bfq_release_process_ref() before doing
> the bic_set_bfqq().
> 
> IOW, I think your merge essentially dropped one of the fixes in commit
> b600de2d7d3a ("block, bfq: fix uaf for bfqq in bic_set_bfqq()").
> 
> Maybe there were reasons why that ordering wasn't required any more,
> but it looks funky (and you appear to have correctly merged the other
> case in bfq_check_ioprio_change()).
> 
> Anyway, this is just a nit-picky email saying that I'm pretty sure
> I've done the merge right, but since it doesn't match what you did, I
> thought I'd mention it.
> 
> Worth double-checking this, in other words. I realize you're mostly
> afk this week, so whenever you're back.

I'll double check it. The merge doesn't end up touching any of
bfq_sync_bfqq_move(), just conflicting with:

bfq_check_ioprio_change(), where the release ordering should be upheld,
and

__bfq_bic_change_cgroup(), where it's still done after assigning the
async_bfqq.

I'll double check tomorrow...

-- 
Jens Axboe