From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Fri, 30 Jan 2015 11:22:33 +0100 (CET) Received: from mailapp01.imgtec.com ([195.59.15.196]:61857 "EHLO imgpgp01.kl.imgtec.org" rhost-flags-OK-OK-OK-FAIL) by eddie.linux-mips.org with ESMTP id S27010822AbbA3KWbgpfcu (ORCPT ); Fri, 30 Jan 2015 11:22:31 +0100 Received: from imgpgp01.kl.imgtec.org (imgpgp01.kl.imgtec.org [127.0.0.1]) by imgpgp01.kl.imgtec.org (PGP Universal) with ESMTP id 3597C41F8DB6; Fri, 30 Jan 2015 10:22:26 +0000 (GMT) Received: from mailapp01.imgtec.com ([10.100.180.242]) by imgpgp01.kl.imgtec.org (PGP Universal service); Fri, 30 Jan 2015 10:22:26 +0000 X-PGP-Universal: processed; by imgpgp01.kl.imgtec.org on Fri, 30 Jan 2015 10:22:26 +0000 Received: from KLMAIL01.kl.imgtec.org (unknown [192.168.5.35]) by Websense Email Security Gateway with ESMTPS id 421ACA37C9C33; Fri, 30 Jan 2015 10:22:24 +0000 (GMT) Received: from LEMAIL01.le.imgtec.org (192.168.152.62) by KLMAIL01.kl.imgtec.org (192.168.5.35) with Microsoft SMTP Server (TLS) id 14.3.195.1; Fri, 30 Jan 2015 10:22:25 +0000 Received: from [192.168.154.110] (192.168.154.110) by LEMAIL01.le.imgtec.org (192.168.152.62) with Microsoft SMTP Server (TLS) id 14.3.210.2; Fri, 30 Jan 2015 10:22:24 +0000 Message-ID: <54CB5B59.5050203@imgtec.com> Date: Fri, 30 Jan 2015 10:22:17 +0000 From: James Hogan User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.3.0 MIME-Version: 1.0 To: "Maciej W. Rozycki" , Aaro Koskinen CC: Ralf Baechle , David Daney , , , Hemmo Nieminen , Subject: Re: [PATCH v2 2/2] MIPS: fix kernel lockup or crash after CPU offline/online References: <1421355719-17576-1-git-send-email-aaro.koskinen@iki.fi> <1421355719-17576-2-git-send-email-aaro.koskinen@iki.fi> In-Reply-To: Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="uXRBadiiSiMPOrLi05Xvga7qvTWIcgmhn" X-Originating-IP: [192.168.154.110] X-ESG-ENCRYPT-TAG: b93fcccb Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 45558 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: james.hogan@imgtec.com Precedence: bulk List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-Id: linux-mips X-List-ID: linux-mips List-subscribe: List-owner: List-post: List-archive: X-list: linux-mips --uXRBadiiSiMPOrLi05Xvga7qvTWIcgmhn Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable Hi Maciej, On 30/01/15 09:25, Maciej W. Rozycki wrote: > On Thu, 15 Jan 2015, Aaro Koskinen wrote: >=20 >> As printk() invocation can cause e.g. a TLB miss, printk() cannot be >> called before the exception handlers have been properly initialized. >> This can happen e.g. when netconsole has been loaded as a kernel modul= e >> and the TLB table has been cleared when a CPU was offline. >=20 > Hmm, why can a call to `printk' cause a TLB miss, what's so special ab= out=20 > this function? Does it use kernel mapped addresses for any purpose suc= h=20 > as `vmalloc'? It would be the fact netconsole (or whatever other console is in use) is built as a kernel module, memory for which is allocated from the vmalloc area. Cheers James --uXRBadiiSiMPOrLi05Xvga7qvTWIcgmhn Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBAgAGBQJUy1tgAAoJEGwLaZPeOHZ6FAwQAIn3Ps8ZEZykJZDzwaHyxEhv 3pDoz7S4ZKGvOrXLSN+Ne578xtTPec2BeQgtZRqFjMPJ+xabbNz5bpL1qdrU/Zg6 /B8DHHtAFhk2FK44QuaUECOGUcONPVdgUquKjTxkMWYIKZroix/tfoC5OzgqBTHp cGy6UMG1WDU/4OJT81cjPHbzanA5x5fEjvypVwwMkr+vnMmg92LxVO3cDMAEAH00 1PpdmBOjiKI2TX10fYpwOsIDHMShmCgaCTQ8s25dSZvOl2NSgBrITEyWIDBw0XAY F9lRKmk5nscO1BriWuFj6VF6O3nIxywRgwnYxyUYiK5fyCAdiXYR5+R3g00b+mhN cy30H4r8iV5n0KAeW3TApwGGEVAaf23L+V2ixN94qwt0MDVqOPaRMw4bu/hOlFfy gmzNFemD60PK6bXlkZUZmHwzT548urN+z1O8i6tn76x4xgS8zIrSmj3/3wXqbDT3 Edzrcr43AESfdGMZXoMDFuQjPObqNarY6TCP5jDHPjiAoV6Bp3ci11SEdLvfGCEn f5wfjZ07ZJLZhaQ9wsXrEM4j8rZEb2Ajmtv4XPQ9T0n83qwQeGRktYPVh/et03RQ 46Z7LJHy8Ch9QLsBlNp7AUP+gfkg5+wk5jO042UzQfQ/uemP04m11oOIW+NUQSVU j1++B65AFHsCsC5w1B+z =n1YL -----END PGP SIGNATURE----- --uXRBadiiSiMPOrLi05Xvga7qvTWIcgmhn-- From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailapp01.imgtec.com ([195.59.15.196]:61857 "EHLO imgpgp01.kl.imgtec.org" rhost-flags-OK-OK-OK-FAIL) by eddie.linux-mips.org with ESMTP id S27010822AbbA3KWbgpfcu (ORCPT ); Fri, 30 Jan 2015 11:22:31 +0100 Message-ID: <54CB5B59.5050203@imgtec.com> Date: Fri, 30 Jan 2015 10:22:17 +0000 From: James Hogan MIME-Version: 1.0 Subject: Re: [PATCH v2 2/2] MIPS: fix kernel lockup or crash after CPU offline/online References: <1421355719-17576-1-git-send-email-aaro.koskinen@iki.fi> <1421355719-17576-2-git-send-email-aaro.koskinen@iki.fi> In-Reply-To: Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="uXRBadiiSiMPOrLi05Xvga7qvTWIcgmhn" Return-Path: Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-subscribe: List-owner: List-post: List-archive: To: "Maciej W. Rozycki" , Aaro Koskinen Cc: Ralf Baechle , David Daney , linux-mips@linux-mips.org, linux-kernel@vger.kernel.org, Hemmo Nieminen , stable@vger.kernel.org Message-ID: <20150130102217.novCAnuF7cVPNmnmnYqfqrXReryKy0c_0fAXU7B0fCE@z> --uXRBadiiSiMPOrLi05Xvga7qvTWIcgmhn Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable Hi Maciej, On 30/01/15 09:25, Maciej W. Rozycki wrote: > On Thu, 15 Jan 2015, Aaro Koskinen wrote: >=20 >> As printk() invocation can cause e.g. a TLB miss, printk() cannot be >> called before the exception handlers have been properly initialized. >> This can happen e.g. when netconsole has been loaded as a kernel modul= e >> and the TLB table has been cleared when a CPU was offline. >=20 > Hmm, why can a call to `printk' cause a TLB miss, what's so special ab= out=20 > this function? Does it use kernel mapped addresses for any purpose suc= h=20 > as `vmalloc'? It would be the fact netconsole (or whatever other console is in use) is built as a kernel module, memory for which is allocated from the vmalloc area. Cheers James --uXRBadiiSiMPOrLi05Xvga7qvTWIcgmhn Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBAgAGBQJUy1tgAAoJEGwLaZPeOHZ6FAwQAIn3Ps8ZEZykJZDzwaHyxEhv 3pDoz7S4ZKGvOrXLSN+Ne578xtTPec2BeQgtZRqFjMPJ+xabbNz5bpL1qdrU/Zg6 /B8DHHtAFhk2FK44QuaUECOGUcONPVdgUquKjTxkMWYIKZroix/tfoC5OzgqBTHp cGy6UMG1WDU/4OJT81cjPHbzanA5x5fEjvypVwwMkr+vnMmg92LxVO3cDMAEAH00 1PpdmBOjiKI2TX10fYpwOsIDHMShmCgaCTQ8s25dSZvOl2NSgBrITEyWIDBw0XAY F9lRKmk5nscO1BriWuFj6VF6O3nIxywRgwnYxyUYiK5fyCAdiXYR5+R3g00b+mhN cy30H4r8iV5n0KAeW3TApwGGEVAaf23L+V2ixN94qwt0MDVqOPaRMw4bu/hOlFfy gmzNFemD60PK6bXlkZUZmHwzT548urN+z1O8i6tn76x4xgS8zIrSmj3/3wXqbDT3 Edzrcr43AESfdGMZXoMDFuQjPObqNarY6TCP5jDHPjiAoV6Bp3ci11SEdLvfGCEn f5wfjZ07ZJLZhaQ9wsXrEM4j8rZEb2Ajmtv4XPQ9T0n83qwQeGRktYPVh/et03RQ 46Z7LJHy8Ch9QLsBlNp7AUP+gfkg5+wk5jO042UzQfQ/uemP04m11oOIW+NUQSVU j1++B65AFHsCsC5w1B+z =n1YL -----END PGP SIGNATURE----- --uXRBadiiSiMPOrLi05Xvga7qvTWIcgmhn--