Date: Tue, 17 Mar 2009 09:05:17 -0400 From: Coleman Kane <cokane@FreeBSD.org> To: Bruce Simpson <bms@incunabulum.net> Cc: Sam Leffler <sam@freebsd.org>, current@freebsd.org, freebsd-net <net@freebsd.org> Subject: Re: IGMP+WiFi panic on recent kernel - in igmp_fasttimo() Message-ID: <1237295117.1844.6.camel@localhost> In-Reply-To: <49BF5B8A.4040108@incunabulum.net> References: <1236937253.2282.0.camel@localhost> <49BAEA9F.8020302@incunabulum.net> <49BB0D3E.2020306@incunabulum.net> <49BC1C66.7030400@freebsd.org> <1237233210.84180.20.camel@localhost> <49BEB312.7060105@freebsd.org> <49BF5B8A.4040108@incunabulum.net>
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--=-Sjq3ZGAlAhQnrQx6Ylp2 Content-Type: text/plain Content-Transfer-Encoding: quoted-printable On Tue, 2009-03-17 at 08:12 +0000, Bruce Simpson wrote: > Sam Leffler wrote: > > It is the same issue but the root cause is unclear. There is much=20 > > code that does assumes ifma_protospec might be NULL and checks for=20 > > it. In my case (creating a wlan ifnet and then destroying it on=20 > > eject) the patch below is sufficient. I don't care to dig right now=20 > > to understand how this stuff is supposed to work; it should be clear=20 > > from comments etc but the code is lacking. > > >=20 > This is just to say I've tried to reproduce the 802.11 related=20 > panics, however have hit a brick wall because the PCI-CardBus bridge=20 > does not seem to detect anything in its slot. (1U Itox Expanding Dragon=20 > industrial PC w/a SiteCom branded Ricoh RL475 cardbus card). I tried=20 > unloading if_fxp with IGMPv3 active on the ifnet, and didn't see any=20 > panic, I'm assuming this is OK for the time being. >=20 > Qing Li volunteered to test IGMPv3 out for any VLAN related issues=20 > -- I understand it stacks ifnets in a similar way to that of 802.11 --=20 > however I have had no feedback from him since last week. > So I'm waiting for a HEAD build to a USB2 stick to finish, so I can=20 > try testing nondestructively on my laptop, where I know for sure that=20 > the PCI-CardBus bridge slot works, and I can detach an 802.11 card on=20 > the fly. >=20 > Re ifma_protospec: Yes, there are tricks in the ifnet/in layer which=20 > set it to NULL and look for it to be NULL. I ended up doing it this way=20 > mainly because adding reference counting to ifnet would have simply been=20 > too much work, and it's really a ball that needs to be kicked around at=20 > a dev summit. However time presses on and it's better to get SOMETHING=20 > out there. > Most likely the IGMPv3 changes are hitting this in the 802.11 case=20 > somehow, I don't have a complete picture of how/why/what's going on, and=20 > have been relying on feedback from others so far. >=20 > cheers > BMS >=20 Today I played with it a bit. I've been unable to produce the crash on my wired (if_bge) interface, however it happens regularly on my wireless (ndis0/wlan0) interface. I was unable to get a core dump for other reasons. However, on my system I do not get the crash if I turn off avahi_daemon (set avahi_daemon_enable=3D"NO" in /etc/rc.conf). I tried booting to single user, ran dhclient on wlan0 (after setting it up properly), and then proceeded to boot the system multi-user. As soon as avahi went live, the kernel panicked, as above. If you are looking for a reliable test case, this might be it for you, but I think you need a wlan interface to test it with: * Install net/avahi from ports * Set avahi_daemon_enable=3D"YES" in rc.conf * Configure VAP params for wlan0 card in rc.conf * Log in and run "dhclient wlan0" to trigger the panic --=20 Coleman Kane --=-Sjq3ZGAlAhQnrQx6Ylp2 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (FreeBSD) iEYEABECAAYFAkm/oAkACgkQcMSxQcXat5d9bACfRFTSKGJwQz9p3IH4nJpwmRNH WwwAn0i08lyyE+njrKI1Osb13gq93PoZ =XuDQ -----END PGP SIGNATURE----- --=-Sjq3ZGAlAhQnrQx6Ylp2--
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