From: Daniel Axtens <dja@axtens.net>
To: Daniel Borkmann <daniel@iogearbox.net>
Cc: Dmitry Vyukov <dvyukov@google.com>,
syzbot <syzbot+82e323920b78d54aaed5@syzkaller.appspotmail.com>,
kasan-dev <kasan-dev@googlegroups.com>,
Andrii Nakryiko <andriin@fb.com>,
Alexei Starovoitov <ast@kernel.org>, bpf <bpf@vger.kernel.org>,
Martin KaFai Lau <kafai@fb.com>,
LKML <linux-kernel@vger.kernel.org>,
netdev <netdev@vger.kernel.org>, Song Liu <songliubraving@fb.com>,
syzkaller-bugs <syzkaller-bugs@googlegroups.com>,
Yonghong Song <yhs@fb.com>,
Andrey Ryabinin <aryabinin@virtuozzo.com>
Subject: Re: BUG: unable to handle kernel paging request in pcpu_alloc
Date: Fri, 06 Dec 2019 00:10:41 +1100 [thread overview]
Message-ID: <871rtiex4e.fsf@dja-thinkpad.axtens.net> (raw)
In-Reply-To: <20191205125900.GB29780@localhost.localdomain>
Daniel Borkmann <daniel@iogearbox.net> writes:
> On Thu, Dec 05, 2019 at 03:35:21PM +1100, Daniel Axtens wrote:
>> >> HEAD commit: 1ab75b2e Add linux-next specific files for 20191203
>> >> git tree: linux-next
>> >> console output: https://syzkaller.appspot.com/x/log.txt?x=10edf2eae00000
>> >> kernel config: https://syzkaller.appspot.com/x/.config?x=de1505c727f0ec20
>> >> dashboard link: https://syzkaller.appspot.com/bug?extid=82e323920b78d54aaed5
>> >> compiler: gcc (GCC) 9.0.0 20181231 (experimental)
>> >> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=156ef061e00000
>> >> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11641edae00000
>> >>
>> >> IMPORTANT: if you fix the bug, please add the following tag to the commit:
>> >> Reported-by: syzbot+82e323920b78d54aaed5@syzkaller.appspotmail.com
>> >
>> > +Daniel, is it the same as:
>> > https://syzkaller.appspot.com/bug?id=f6450554481c55c131cc23d581fbd8ea42e63e18
>> > If so, is it possible to make KASAN detect this consistently with the
>> > same crash type so that syzbot does not report duplicates?
>>
>> It looks like both of these occur immediately after failure injection. I
>> think my assumption that I could ignore the chance of failures in the
>> per-cpu allocation path will have to be revisited. That's annoying.
>>
>> I'll try to spin something today but Andrey feel free to pip me at the
>> post again :)
>>
>> I'm not 100% confident to call them dups just yet, but I'm about 80%
>> confident that they are.
>
> Ok. Double checked BPF side yesterday night, but looks sane to me and the
> fault also hints into pcpu_alloc() rather than BPF code. Daniel, from your
> above reply, I read that you are aware of how the bisected commit would
> have caused the fault?
Yes, this one is on me - I did not take into account the brutal
efficiency of the fault injector when implementing my KASAN support for
vmalloc areas. I have a fix, I'm just doing final tests now.
Regards,
Daniel
>
> Thanks,
> Daniel
>
> --
> You received this message because you are subscribed to the Google Groups "kasan-dev" group.
> To unsubscribe from this group and stop receiving emails from it, send an email to kasan-dev+unsubscribe@googlegroups.com.
> To view this discussion on the web visit https://groups.google.com/d/msgid/kasan-dev/20191205125900.GB29780%40localhost.localdomain.
next prev parent reply other threads:[~2019-12-05 13:10 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-04 8:15 BUG: unable to handle kernel paging request in pcpu_alloc syzbot
2019-12-04 8:18 ` Dmitry Vyukov
2019-12-05 4:35 ` Daniel Axtens
2019-12-05 12:59 ` Daniel Borkmann
2019-12-05 13:10 ` Daniel Axtens [this message]
2019-12-05 13:19 ` Daniel Borkmann
2019-12-04 17:25 ` syzbot
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=871rtiex4e.fsf@dja-thinkpad.axtens.net \
--to=dja@axtens.net \
--cc=andriin@fb.com \
--cc=aryabinin@virtuozzo.com \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=dvyukov@google.com \
--cc=kafai@fb.com \
--cc=kasan-dev@googlegroups.com \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=songliubraving@fb.com \
--cc=syzbot+82e323920b78d54aaed5@syzkaller.appspotmail.com \
--cc=syzkaller-bugs@googlegroups.com \
--cc=yhs@fb.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 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).