From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761927AbXGTGlr (ORCPT ); Fri, 20 Jul 2007 02:41:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753723AbXGTGlk (ORCPT ); Fri, 20 Jul 2007 02:41:40 -0400 Received: from cantor.suse.de ([195.135.220.2]:40778 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751338AbXGTGlj (ORCPT ); Fri, 20 Jul 2007 02:41:39 -0400 From: Neil Brown To: "Satyam Sharma" Date: Fri, 20 Jul 2007 16:41:33 +1000 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <18080.22813.143226.671265@notabene.brown> Cc: "David CHANIAL" , "Linux Kernel Mailinglist" Subject: Re: BUG: unable to handle kernel NULL pointer dereference - nfs v3 In-Reply-To: message from Satyam Sharma on Thursday July 19 References: <200707160638.15750.david.ml@euro-web.fr> <18076.42052.961808.528867@notabene.brown> X-Mailer: VM 7.19 under Emacs 21.4.1 X-face: [Gw_3E*Gng}4rRrKRYotwlE?.2|**#s9D Ugh, not a good day for me today ... my earlier conclusion was right, > but not the reasoning behind it ... hopefully this time I'll do better :-) Looks good. Thanks for your helpful analysis. > > 0x34 bytes is the offset of ex_uuid in struct fh_export. > %ecx == 0, which means ex_uuid was NULL. Yup. That shouldn't happen, but I can see that it is possible. There was another case were ex_uuid could conceivably be referenced while NULL that I fixed a little while ago. Looks like I need to fix this one too. Something like the following. Thanks, NeilBrown Signed-off-by: Neil Brown ### Diffstat output ./fs/nfsd/nfsfh.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) diff .prev/fs/nfsd/nfsfh.c ./fs/nfsd/nfsfh.c --- .prev/fs/nfsd/nfsfh.c 2007-07-13 17:41:48.000000000 +1000 +++ ./fs/nfsd/nfsfh.c 2007-07-20 12:53:36.000000000 +1000 @@ -566,13 +566,23 @@ enum fsid_source fsid_source(struct svc_ case FSID_DEV: case FSID_ENCODE_DEV: case FSID_MAJOR_MINOR: - return FSIDSOURCE_DEV; + if (fhp->fh_export->ex_dentry->d_inode->i_sb->s_type->fs_flags + & FS_REQUIRES_DEV) + return FSIDSOURCE_DEV; + break; case FSID_NUM: - return FSIDSOURCE_FSID; - default: if (fhp->fh_export->ex_flags & NFSEXP_FSID) return FSIDSOURCE_FSID; - else - return FSIDSOURCE_UUID; + break; + default: + break; } + /* either a UUID type filehandle, or the filehandle doesn't + * match the export. + */ + if (fhp->fh_export->ex_flags & NFSEXP_FSID) + return FSIDSOURCE_FSID; + if (fhp->fh_export->ex_uuid) + return FSIDSOURCE_UUID; + return FSIDSOURCE_DEV; }