linux-mm.kvack.org archive mirror
 help / color / mirror / Atom feed
From: Michal Hocko <mhocko@kernel.org>
To: Peter Xu <peterx@redhat.com>
Cc: linux-kernel@vger.kernel.org,
	Linus Torvalds <torvalds@linux-foundation.org>,
	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: Wed, 8 Apr 2020 12:21:28 +0200	[thread overview]
Message-ID: <20200408102128.GX18914@dhcp22.suse.cz> (raw)
In-Reply-To: <20200408014010.80428-2-peterx@redhat.com>

On Tue 07-04-20 21:40:09, Peter Xu wrote:
> lookup_node() uses gup to pin the page and get node information.  It
> checks against ret>=0 assuming the page will be filled in.  However
> it's also possible that gup will return zero, for example, when the
> thread is quickly killed with a fatal signal.  Teach lookup_node() to
> gracefully return an error -EFAULT if it happens.
> 
> Meanwhile, initialize "page" to NULL to avoid potential risk of
> exploiting the pointer.
> 
> Reported-by: syzbot+693dc11fcb53120b5559@syzkaller.appspotmail.com
> Fixes: 4426e945df58 ("mm/gup: allow VM_FAULT_RETRY for multiple times")

I am not familiar with thic commit but shouldn't gup return ERESTARTSYS
on a fatal signal?
-- 
Michal Hocko
SUSE Labs


  reply	other threads:[~2020-04-08 10:21 UTC|newest]

Thread overview: 56+ 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 [this message]
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
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
2020-04-21  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 18:16       ` Andrew Morton
2020-04-09 18:53         ` Linus Torvalds
2020-04-09 19:12           ` Andrew Morton
2020-04-09 19:46             ` Linus Torvalds
2020-04-09 19:56               ` Matthew Wilcox
2020-04-09 19:58                 ` Linus Torvalds
2020-04-09 20:27                   ` Eric Biggers
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 16:32     ` Linus Torvalds
2020-04-09 16:58       ` Qian Cai
2020-04-09 17:05         ` Linus Torvalds
2020-04-09 17:58           ` Qian Cai
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 11:59             ` Qian Cai
2020-04-14 12:05               ` Dmitry Vyukov
2020-04-14 19:28             ` Dan Rue
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
2020-04-14  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=20200408102128.GX18914@dhcp22.suse.cz \
    --to=mhocko@kernel.org \
    --cc=akpm@linux-foundation.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=peterx@redhat.com \
    --cc=syzbot+693dc11fcb53120b5559@syzkaller.appspotmail.com \
    --cc=torvalds@linux-foundation.org \
    /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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).