Date: Tue, 25 Jun 2019 23:13:29 +0300 From: "Andrey V. Elsukov" <bu7cher@yandex.ru> To: Larry Rosenman <ler@lerctr.org> Cc: freebsd-net@freebsd.org, freebsd-current@freebsd.org Subject: Re: ng_snd_item: Panic? Message-ID: <7b4c697c-e924-deb8-d227-2d188b8f8483@yandex.ru> In-Reply-To: <acb3a55035be48426fdaa49c4820a5fc@lerctr.org> References: <20190624183200.hu4vzocjsopjsnnz@ler-imac.local> <c3de35e2-0954-9811-8600-85e059c61464@yandex.ru> <d1d85d35671198f1cb41f4f781a91587@lerctr.org> <f5c32384-ae8c-7dcf-cff7-b2053bb8a03b@yandex.ru> <acb3a55035be48426fdaa49c4820a5fc@lerctr.org>
next in thread | previous in thread | raw e-mail | index | archive | help
This is an OpenPGP/MIME signed message (RFC 4880 and 3156)
--pkXM9hOnC7Epjpsk1PDXC3jciX3wIAszu
Content-Type: multipart/mixed; boundary="LAsyanrEHoxlPz6O4Ca6I4nKHVYwDfizP";
protected-headers="v1"
From: "Andrey V. Elsukov" <bu7cher@yandex.ru>
To: Larry Rosenman <ler@lerctr.org>
Cc: freebsd-net@freebsd.org, freebsd-current@freebsd.org
Message-ID: <7b4c697c-e924-deb8-d227-2d188b8f8483@yandex.ru>
Subject: Re: ng_snd_item: Panic?
References: <20190624183200.hu4vzocjsopjsnnz@ler-imac.local>
<c3de35e2-0954-9811-8600-85e059c61464@yandex.ru>
<d1d85d35671198f1cb41f4f781a91587@lerctr.org>
<f5c32384-ae8c-7dcf-cff7-b2053bb8a03b@yandex.ru>
<acb3a55035be48426fdaa49c4820a5fc@lerctr.org>
In-Reply-To: <acb3a55035be48426fdaa49c4820a5fc@lerctr.org>
--LAsyanrEHoxlPz6O4Ca6I4nKHVYwDfizP
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: quoted-printable
On 25.06.2019 15:59, Larry Rosenman wrote:
> On 06/25/2019 4:18 am, Andrey V. Elsukov wrote:
>> On 24.06.2019 23:10, Larry Rosenman wrote:
>>>>> #5=C2=A0 0xffffffff828ee5b7 in ng_snd_item (item=3D0xfffff8021e3b4d=
80,
>>>>> flags=3D0)
>>>>> =C2=A0=C2=A0=C2=A0 at /usr/src/sys/netgraph/ng_base.c:2252
>>>>
>>>> It looks like you use some netgraph based ethernet interface.
>>>> The system got received ARP request and is going to send the reply,
>>>> but somehow mbuf with this ARP request has initialized m_next pointe=
r,
>>>> thus it is considered as a chain of mbufs.
>>>>
>>>> in_arpinput() reuses received mbuf to construct the reply, but it
>>>> doesn't check that an mbut is a chain. It just sets m_len and sends =
it.
>>>> Then since you have INVARIANTS in your kernel, the netgraph code che=
ck
>>>> the actual length of the chain, and it doesn't match to m_len. It
>>>> panics.
>>>
>>>
>>> so, is this a bug?=C2=A0 Timing race? Other?
>>
>> I think we should determine that my assumption is correct :)
>> Can you show the output of the following commands from the kgdb for th=
is
>> core?
>>
>> (kgdb) f 7
>> (kgdb) p *m
>> (kgdb) p *m->m_next
>=20
>=20
> (kgdb) fr 7
> #7=C2=A0 0xffffffff805b1e43 in ether_output (ifp=3D<optimized out>,
> m=3D0xfffff81f59eefb00, dst=3D0xfffffe012628d740, ro=3D<optimized out>)=
at
> /usr/src/sys/net/if_ethersubr.c:430
> 430=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 i=
f ((error =3D (*ng_ether_output_p)(ifp, &m)) !=3D 0) {
I failed to track the possible way to get this.
Please, show the output of the following commands:
(kgdb) f 7
(kgdb) p/x (u_char[42])m->m_data
(kgdb) p/x (u_char[1372]m->m_next->m_data
Did you used this configuration for the long time and these panics were
the first time?
--=20
WBR, Andrey V. Elsukov
--LAsyanrEHoxlPz6O4Ca6I4nKHVYwDfizP--
--pkXM9hOnC7Epjpsk1PDXC3jciX3wIAszu
Content-Type: application/pgp-signature; name="signature.asc"
Content-Description: OpenPGP digital signature
Content-Disposition: attachment; filename="signature.asc"
-----BEGIN PGP SIGNATURE-----
Comment: Using GnuPG with Thunderbird - https://www.enigmail.net/
iQEzBAEBCAAdFiEE5lkeG0HaFRbwybwAAcXqBBDIoXoFAl0SgGkACgkQAcXqBBDI
oXobnwgAu+qATxqLM5x9lj50JU7DtSD++QN++XiKTTdv2o/Ihai26OnW5EDRrfzh
GcefzF47UvJTsBhf48y9Ws6XoMLShCv6FWE6iP5b2B7KwQ8rYVbpu5eNfQOqamqd
lIX0j1q+xvqs+mx5F5XvC3QWNu1+lS1Pdgw3ay7i8qNfBTDJHg6NeUcA2uTz/iVX
eiG3pkXigTTnLIquPmg9OpHUgZWAmpzFAvl36aoWfzVKUBxYS8CVYnYwAngUf4UR
3xIBvy0UyuWbX/7xyHJzF6PdUA77M6Mm7ti5Qly2x28SDDL3Jl4jglmzX4sQ7TdY
ZwJuHwKTvpCucy1OXx4/73SI3A2pyA==
=Y/JP
-----END PGP SIGNATURE-----
--pkXM9hOnC7Epjpsk1PDXC3jciX3wIAszu--
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?7b4c697c-e924-deb8-d227-2d188b8f8483>