Return-path: Received: from crystal.sipsolutions.net ([195.210.38.204]:55172 "EHLO sipsolutions.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751453AbXLXV5K (ORCPT ); Mon, 24 Dec 2007 16:57:10 -0500 Subject: Re: Strange mac80211 oops From: Johannes Berg To: Michael Buesch Cc: linux-wireless@vger.kernel.org, Daniel Drake , John Linville In-Reply-To: <1198532736.4103.44.camel@johannes.berg> (sfid-20071224_214550_097878_F699D24B) References: <200712242237.28913.mb@bu3sch.de> <1198532736.4103.44.camel@johannes.berg> (sfid-20071224_214550_097878_F699D24B) Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-zCWsqE1ra63Jig6yHSfy" Date: Mon, 24 Dec 2007 22:57:03 +0100 Message-Id: <1198533423.4103.46.camel@johannes.berg> (sfid-20071224_215715_804934_D07F8E7D) Mime-Version: 1.0 Sender: linux-wireless-owner@vger.kernel.org List-ID: --=-zCWsqE1ra63Jig6yHSfy Content-Type: text/plain Content-Transfer-Encoding: quoted-printable On Mon, 2007-12-24 at 22:45 +0100, Johannes Berg wrote: > > [ 98.415423] ------------[ cut here ]------------ > > [ 98.415627] Badness at e221c924 [verbose debug info unavailable] >=20 > > [ 98.416905] NIP [e221c924] __ieee80211_rx+0x48c/0xd44 [mac80211] >=20 > ieee80211_rx_monitor() is inlined into __ieee80211_rx() and that +0x48c > is quite a high number, so I'm guessing it's this: >=20 > /* > * Drivers are required to align the payload data to a four-byte > * boundary, so the last two bits of the address where it starts > * may not be set. The header is required to be directly before > * the payload data, padding like atheros hardware adds which is > * inbetween the 802.11 header and the payload is not supported, > * the driver is required to move the 802.11 header further back > * in that case. > */ > hdrlen =3D ieee80211_get_hdrlen(rx.fc); > WARN_ON_ONCE(((unsigned long)(skb->data + hdrlen)) & 3); Yup, that's what it is, Michael sent me the assembly, __ieee80211_rx starts at 0x1990 and we find at 0x1990+0x48c =3D=3D 0x1e1c 1df8: 48 00 00 01 bl 1df8 <__ieee80211_rx+0x468> 1df8: R_PPC_REL24 ieee80211_get_hdrlen 1dfc: 80 18 00 a0 lwz r0,160(r24) 1e00: 7c 00 1a 14 add r0,r0,r3 1e04: 70 09 00 03 andi. r9,r0,3 1e08: 41 a2 00 2c beq+ 1e34 <__ieee80211_rx+0x4a4> 1e0c: 3d 20 00 00 lis r9,0 1e0e: R_PPC_ADDR16_HA .sbss 1e10: 80 09 00 00 lwz r0,0(r9) 1e12: R_PPC_ADDR16_LO .sbss 1e14: 7c 00 00 34 cntlzw r0,r0 1e18: 54 00 d9 7e rlwinm r0,r0,27,5,31 1e1c: 0f 00 00 00 twnei r0,0 which is exactly the WARN_ON_ONCE above. johannes --=-zCWsqE1ra63Jig6yHSfy Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Comment: Johannes Berg (powerbook) iQIVAwUAR3ArLaVg1VMiehFYAQKS4Q/9FlU/hfbZvO8xoKe6z5uealRmixqxQG8h 8Vt47ee3f5GN+hHu7O5gE2CnH/qV2t8ynhuRoSLetVlUsnSLEzEgfLwlf+tQdvJh KiQEJ3oAWVviVHX50XiEpMXKv6r4vthLBasD5I+bxJ0uWhsJJb5rv+qan8SP8BUX lL7UOYsfCI7sJyr8aUImL+TYfXuUHXpc63t+I1X8q3effSqS9F34xFxRHpYloFHI lKQZzXfIs+X+3VWqKrHo6PdlCJs4U6XQJcRwb1CNHo0FA/SGKBfhsSDGvqinKpzD B24DTt0Qa23FPjK0r7LJq+235nz7wi2x8mBlGyVb3/phLEwu0R3goi74L7C5KkTt U5FYdxQj0xbHqOb5K/+m/x+3lH9hKQdMpWTb1TtzJAvfKUK8ZoTTKzx0lGxNOpKi 9NHg5HwtP967SQeN+k0cQdI0EmyEnpZVHjbTON4YxxI2wVOHrO4RExd9+sYpxsMe n28U6f0Saz5p78RzJ5BdGRNluGA5o7i3rtWHeXdZMg8ghMz527CA1ud1Taz77cQR Ie8/xTQ1OvIaASFtipA6zylBmvoTFCMLLlA3Wb/9O6txPRRHJxcF9bRAx3FohcNI mau0Dd8ueKwRmtODqqLhheUxRdOKyZIuePfgsp/BOc5faBZMgdtUQ2/FcFCTwjT5 bzFOsiwVnkw= =LsLl -----END PGP SIGNATURE----- --=-zCWsqE1ra63Jig6yHSfy--