Re: [PATCH] block, bfq: fix uaf for bfqq in bic_set_bfqq()

[Yu Kuai]

Hi,

在 2023/01/30 5:51, Jens Axboe 写道:
> On 1/28/23 6:38 PM, Yu Kuai wrote:
> > Hi, Jens
> >
> > 在 2023/01/13 17:44, Yu Kuai 写道:
> > > After commit 64dc8c732f5c ("block, bfq: fix possible uaf for 'bfqq->bic'"),
> > > bic->bfqq will be accessed in bic_set_bfqq(), however, in some context
> > > bic->bfqq will be freed first, and bic_set_bfqq() is called with the freed
> > > bic->bfqq.
> > >
> > > Fix the problem by always freeing bfqq after bic_set_bfqq().
> >
> > Sorry that I send this patch will wrong email, and you might missed this
> > patch.
> >
> > Can you apply this patch? This patch can't be applied directly to lower
> > version due to Paolo's patchset, I'll send lts patch seperately.
>
> I'm confused... So this patch only applies to the 6.3 branch, yet we
> need it in 6.2 as far as I can tell. Why isn't it against block-6.2
> then?

Ok, I'll send a new patch against block-6.2.

Thanks,
Kuai