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From: Andrew Morton <akpm@linux-foundation.org>
To: syzbot <syzbot+b4501d3e966ff59f6090@syzkaller.appspotmail.com>
Cc: bgeffon@google.com, linux-kernel@vger.kernel.org,
	linux-mm@kvack.org, peterx@redhat.com,
	syzkaller-bugs@googlegroups.com, torvalds@linux-foundation.org
Subject: Re: KASAN: user-memory-access Read in put_page
Date: Mon, 6 Apr 2020 16:21:18 -0700	[thread overview]
Message-ID: <20200406162118.4a91d61e8f506a9e728339f4@linux-foundation.org> (raw)
In-Reply-To: <00000000000021008f05a2a34336@google.com>

On Mon, 06 Apr 2020 11:16:13 -0700 syzbot <syzbot+b4501d3e966ff59f6090@syzkaller.appspotmail.com> wrote:

> Hello,
> 
> syzbot found the following crash on:
> 
> HEAD commit:    bef7b2a7 Merge tag 'devicetree-for-5.7' of git://git.kerne..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=16940efbe00000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=f72ba8a207627d60
> dashboard link: https://syzkaller.appspot.com/bug?extid=b4501d3e966ff59f6090
> compiler:       clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81)
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15d79efbe00000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1705901be00000
> 
> The bug was bisected to:
> 
> commit 4426e945df588f2878affddf88a51259200f7e29
> Author: Peter Xu <peterx@redhat.com>
> Date:   Thu Apr 2 04:08:49 2020 +0000
> 
>     mm/gup: allow VM_FAULT_RETRY for multiple times
> 
> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1441b1fbe00000
> final crash:    https://syzkaller.appspot.com/x/report.txt?x=1641b1fbe00000
> console output: https://syzkaller.appspot.com/x/log.txt?x=1241b1fbe00000

Thanks.  This looks like a duplicate of your report
syzbot+693dc11fcb53120b5559@syzkaller.appspotmail.com ("BUG: unable to
handle kernel paging request in kernel_get_mempolicy").

The bisection is believable but I can't spot why 4426e945df58 would
have messed up get_user_pages_locked() in this fashion - I've asked
Peter to take a look.


      reply	other threads:[~2020-04-06 23:21 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-06 18:16 syzbot
2020-04-06 23:21 ` Andrew Morton [this message]

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