From patchwork Thu Jan 16 23:16:39 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 233689 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3D3ECC33CAF for ; Thu, 16 Jan 2020 23:46:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0F03820663 for ; Thu, 16 Jan 2020 23:46:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579218369; bh=wHSHb/MDBqahkrdh6IvxEuw+l7mYeRaaQEPep9xZhdw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=uqHdUHhYmrBLOndR0rADtGV9PK5qnngyJJG3THJuZWBxyGguiBBy/3to0mpVBQgOx B9MFfNXn0m07fe+SGUnSnMW4oOLgqP2xJiemptsO+2pcnw3YStLDfkgTPDyNhhdfhO N4m8iT0u43G9Y3uAOaPt0pr82/fZVt0rqfWnFs0o= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731589AbgAPXqI (ORCPT ); Thu, 16 Jan 2020 18:46:08 -0500 Received: from mail.kernel.org ([198.145.29.99]:50122 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387782AbgAPXWU (ORCPT ); Thu, 16 Jan 2020 18:22:20 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5702C2073A; Thu, 16 Jan 2020 23:22:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579216939; bh=wHSHb/MDBqahkrdh6IvxEuw+l7mYeRaaQEPep9xZhdw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Z9cbGZw+LM7M+oMuBbbd68Z+b5Odof7ujVoOPkEADDLSOTI83bVryXgiEzoYWBUpQ sBQDea9Poihj5l8Inxv1lgJJpXX7SEZallpNWsaSM57NKDJklo6fUgO44Paj6Ojitn /hlkfUDRnOV6a9rHq6GRWAqroorTJ25ue+wtUjuY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Al Viro , David Howells , Linus Torvalds Subject: [PATCH 5.4 082/203] afs: Fix use-after-loss-of-ref Date: Fri, 17 Jan 2020 00:16:39 +0100 Message-Id: <20200116231752.179454016@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200116231745.218684830@linuxfoundation.org> References: <20200116231745.218684830@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: David Howells commit 40a708bd622b78582ae3d280de29b09b50bd04c0 upstream. afs_lookup() has a tracepoint to indicate the outcome of d_splice_alias(), passing it the inode to retrieve the fid from. However, the function gave up its ref on that inode when it called d_splice_alias(), which may have failed and dropped the inode. Fix this by caching the fid. Fixes: 80548b03991f ("afs: Add more tracepoints") Reported-by: Al Viro Signed-off-by: David Howells Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- fs/afs/dir.c | 12 +++++++----- include/trace/events/afs.h | 12 +++--------- 2 files changed, 10 insertions(+), 14 deletions(-) --- a/fs/afs/dir.c +++ b/fs/afs/dir.c @@ -908,6 +908,7 @@ static struct dentry *afs_lookup(struct unsigned int flags) { struct afs_vnode *dvnode = AFS_FS_I(dir); + struct afs_fid fid = {}; struct inode *inode; struct dentry *d; struct key *key; @@ -957,15 +958,16 @@ static struct dentry *afs_lookup(struct dentry->d_fsdata = (void *)(unsigned long)dvnode->status.data_version; } + + if (!IS_ERR_OR_NULL(inode)) + fid = AFS_FS_I(inode)->fid; + d = d_splice_alias(inode, dentry); if (!IS_ERR_OR_NULL(d)) { d->d_fsdata = dentry->d_fsdata; - trace_afs_lookup(dvnode, &d->d_name, - inode ? AFS_FS_I(inode) : NULL); + trace_afs_lookup(dvnode, &d->d_name, &fid); } else { - trace_afs_lookup(dvnode, &dentry->d_name, - IS_ERR_OR_NULL(inode) ? NULL - : AFS_FS_I(inode)); + trace_afs_lookup(dvnode, &dentry->d_name, &fid); } return d; } --- a/include/trace/events/afs.h +++ b/include/trace/events/afs.h @@ -915,9 +915,9 @@ TRACE_EVENT(afs_call_state, TRACE_EVENT(afs_lookup, TP_PROTO(struct afs_vnode *dvnode, const struct qstr *name, - struct afs_vnode *vnode), + struct afs_fid *fid), - TP_ARGS(dvnode, name, vnode), + TP_ARGS(dvnode, name, fid), TP_STRUCT__entry( __field_struct(struct afs_fid, dfid ) @@ -928,13 +928,7 @@ TRACE_EVENT(afs_lookup, TP_fast_assign( int __len = min_t(int, name->len, 23); __entry->dfid = dvnode->fid; - if (vnode) { - __entry->fid = vnode->fid; - } else { - __entry->fid.vid = 0; - __entry->fid.vnode = 0; - __entry->fid.unique = 0; - } + __entry->fid = *fid; memcpy(__entry->name, name->name, __len); __entry->name[__len] = 0; ),