From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH] nfsd: fix NULL dereference in nfsd_statfs() Date: Fri, 13 Aug 2010 16:42:27 +0200 Message-ID: <20100813144227.GA9155@lst.de> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "J. Bruce Fields" , Neil Brown , Al Viro , Christoph Hellwig , linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org To: Takashi Iwai Return-path: Received: from verein.lst.de ([213.95.11.210]:43326 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761678Ab0HMOmc (ORCPT ); Fri, 13 Aug 2010 10:42:32 -0400 In-Reply-To: Sender: linux-nfs-owner@vger.kernel.org List-ID: On Fri, Aug 13, 2010 at 03:53:49PM +0200, Takashi Iwai wrote: > The commit ebabe9a9001af0af56c0c2780ca1576246e7a74b > pass a struct path to vfs_statfs > introduced the struct path initialization, and this seems to trigger > an Oops on my machine. > > fh_dentry field may be NULL and set later in fh_verify(), thus the > initialization of path must be after fh_verify(). Thanks, the patch looks good. Reviewed-by: Christoph Hellwig > diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c > index 96360a8..661a6cf 100644 > --- a/fs/nfsd/vfs.c > +++ b/fs/nfsd/vfs.c > @@ -2033,15 +2033,17 @@ out: > __be32 > nfsd_statfs(struct svc_rqst *rqstp, struct svc_fh *fhp, struct kstatfs *stat, int access) > { > - struct path path = { > - .mnt = fhp->fh_export->ex_path.mnt, > - .dentry = fhp->fh_dentry, > - }; > __be32 err; > > err = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP | access); > - if (!err && vfs_statfs(&path, stat)) > - err = nfserr_io; > + if (!err) { > + struct path path = { > + .mnt = fhp->fh_export->ex_path.mnt, > + .dentry = fhp->fh_dentry, > + }; > + if (vfs_statfs(&path, stat)) > + err = nfserr_io; > + } > return err; > } > > -- > 1.7.2.1 ---end quoted text---