All of lore.kernel.org
 help / color / mirror / Atom feed
From: Linus Torvalds <torvalds@linux-foundation.org>
To: Michal Hocko <mhocko@kernel.org>
Cc: Peter Xu <peterx@redhat.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Linux-MM <linux-mm@kvack.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	syzbot+693dc11fcb53120b5559@syzkaller.appspotmail.com
Subject: Re: [PATCH 1/2] mm/mempolicy: Allow lookup_node() to handle fatal signal
Date: Thu, 9 Apr 2020 09:42:20 -0700	[thread overview]
Message-ID: <CAHk-=whwRqkwdaJQf4g0-Evd6RmXR3dkkKyfnPjbnkeia=b1ug@mail.gmail.com> (raw)
In-Reply-To: <20200409070253.GB18386@dhcp22.suse.cz>

On Thu, Apr 9, 2020 at 12:03 AM Michal Hocko <mhocko@kernel.org> wrote:
>
> This patch however doesn't go all the way to revert it because 0 return
> value is impossible.

I'm not convinced it's impossible. And if it is, then the current code
is harmless.

Now, I do agree that we probably should go through and clarify the
whole range of different get_user_pages() cases of returning zero (or
not doing so), but right now it's so confusing that I'd prefer to keep
that (possibly unnecessary) belt-and-suspenders check for zero in
there.

If/when somebody actually does a real audit and the result is "these
functions cannot return zero" and it's documented, then we can remove
those checks.

Ok?

              Linus

  parent reply	other threads:[~2020-04-09 16:42 UTC|newest]

Thread overview: 71+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-08  1:40 [PATCH 0/2] mm: Two small fixes for recent syzbot reports Peter Xu
2020-04-08  1:40 ` [PATCH 1/2] mm/mempolicy: Allow lookup_node() to handle fatal signal Peter Xu
2020-04-08 10:21   ` Michal Hocko
2020-04-08 14:20     ` Peter Xu
2020-04-08 14:30       ` Michal Hocko
2020-04-08 15:24         ` Peter Xu
2020-04-08 15:26           ` Michal Hocko
2020-04-09  7:02   ` Michal Hocko
2020-04-09 12:52     ` Peter Xu
2020-04-09 13:00       ` Peter Xu
2020-04-09 13:53       ` Michal Hocko
2020-04-09 16:42     ` Linus Torvalds [this message]
2020-04-09 16:42       ` Linus Torvalds
2020-04-14 11:04       ` Michal Hocko
2020-04-14 13:49         ` Peter Xu
2020-04-14 14:18           ` Michal Hocko
2020-04-20 12:47         ` Michal Hocko
2020-04-20 17:31           ` Linus Torvalds
2020-04-20 17:31             ` Linus Torvalds
2020-04-21  7:09             ` Michal Hocko
2020-04-08  1:40 ` [PATCH 2/2] mm/gup: Mark lock taken only after a successful retake Peter Xu
2020-04-09  0:47 ` [PATCH 0/2] mm: Two small fixes for recent syzbot reports Andrew Morton
2020-04-09 11:49   ` Matthew Wilcox
2020-04-09 13:00     ` Dmitry Vyukov
2020-04-09 13:00       ` Dmitry Vyukov
2020-04-09 18:16       ` Andrew Morton
2020-04-09 18:53         ` Linus Torvalds
2020-04-09 18:53           ` Linus Torvalds
2020-04-09 19:12           ` Andrew Morton
2020-04-09 19:46             ` Linus Torvalds
2020-04-09 19:46               ` Linus Torvalds
2020-04-09 19:56               ` Matthew Wilcox
2020-04-09 19:58                 ` Linus Torvalds
2020-04-09 19:58                   ` Linus Torvalds
2020-04-09 20:27                   ` Eric Biggers
2020-04-09 20:34                     ` Linus Torvalds
2020-04-09 20:34                       ` Linus Torvalds
2020-04-09 23:34                       ` Stephen Rothwell
2020-04-10  1:11                       ` Theodore Y. Ts'o
2020-04-09 12:55   ` Dmitry Vyukov
2020-04-09 12:55     ` Dmitry Vyukov
2020-04-09 16:32     ` Linus Torvalds
2020-04-09 16:32       ` Linus Torvalds
2020-04-09 16:58       ` Qian Cai
2020-04-09 17:05         ` Linus Torvalds
2020-04-09 17:05           ` Linus Torvalds
2020-04-09 17:58           ` Qian Cai
2020-04-09 18:06             ` Linus Torvalds
2020-04-09 18:06               ` Linus Torvalds
2020-04-09 21:14               ` Qian Cai
2020-04-10 13:12                 ` Tetsuo Handa
2020-04-10 14:26                   ` Qian Cai
2020-04-10 17:26                     ` Andrew Morton
2020-04-10 19:46                       ` Qian Cai
2020-04-09 23:29       ` Stephen Rothwell
2020-04-13 22:06         ` Qian Cai
2020-04-13 23:05           ` Jens Axboe
2020-04-14 11:12           ` Dmitry Vyukov
2020-04-14 11:12             ` Dmitry Vyukov
2020-04-14 11:59             ` Qian Cai
2020-04-14 12:05               ` Dmitry Vyukov
2020-04-14 12:05                 ` Dmitry Vyukov
2020-04-14 19:28             ` Dan Rue
2020-04-15 11:09               ` Dmitry Vyukov
2020-04-15 11:09                 ` Dmitry Vyukov
2020-04-15 16:23                 ` Dan Rue
2020-04-16  0:34             ` Stephen Rothwell
2020-05-11 15:29               ` Dmitry Vyukov
2020-05-11 15:29                 ` Dmitry Vyukov
2020-04-14  4:07         ` Hillf Danton
2020-04-14  4:31           ` Jens Axboe

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to='CAHk-=whwRqkwdaJQf4g0-Evd6RmXR3dkkKyfnPjbnkeia=b1ug@mail.gmail.com' \
    --to=torvalds@linux-foundation.org \
    --cc=akpm@linux-foundation.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=mhocko@kernel.org \
    --cc=peterx@redhat.com \
    --cc=syzbot+693dc11fcb53120b5559@syzkaller.appspotmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.