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>