From: Jason Gunthorpe <jgg@nvidia.com>
To: David Hildenbrand <david@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
John Hubbard <jhubbard@nvidia.com>,
linux-mm@kvack.org, Lorenzo Stoakes <lstoakes@gmail.com>,
syzbot+353c7be4964c6253f24a@syzkaller.appspotmail.com
Subject: Re: [PATCH] mm/gup: Do not return 0 from pin_user_pages_fast() for bad args
Date: Wed, 21 Jun 2023 08:38:37 -0300 [thread overview]
Message-ID: <ZJLhPYtes5MLTyXj@nvidia.com> (raw)
In-Reply-To: <d86c82d7-2e45-6de8-dcfa-c1dcac06c49a@redhat.com>
On Wed, Jun 21, 2023 at 01:24:14PM +0200, David Hildenbrand wrote:
> > diff --git a/mm/gup.c b/mm/gup.c
> > index bbe4162365933e..36c587fec574fd 100644
> > --- a/mm/gup.c
> > +++ b/mm/gup.c
> > @@ -2969,7 +2969,7 @@ static int internal_get_user_pages_fast(unsigned long start,
> > start = untagged_addr(start) & PAGE_MASK;
> > len = nr_pages << PAGE_SHIFT;
> > if (check_add_overflow(start, len, &end))
> > - return 0;
> > + return -EOVERFLOW;
>
> I'm curious if there is any sane use case where that could actually trigger.
> Smells like something that should be a WARN_ON_ONCE(), but maybe some
> callers simply pass through what user-space gave them.
Yes, that is pretty common to just pass through.
Thanks,
Jason
prev parent reply other threads:[~2023-06-21 11:38 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-19 18:27 Jason Gunthorpe
2023-06-20 1:38 ` John Hubbard
2023-06-20 21:20 ` Lorenzo Stoakes
2023-06-21 11:24 ` David Hildenbrand
2023-06-21 11:38 ` Jason Gunthorpe [this message]
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