From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1165697AbeE1OdS (ORCPT ); Mon, 28 May 2018 10:33:18 -0400 Received: from mail.kernel.org ([198.145.29.99]:52742 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161584AbeE1Kcl (ORCPT ); Mon, 28 May 2018 06:32:41 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Peter Zijlstra , Will Deacon , Al Viro , Sasha Levin Subject: [PATCH 4.9 143/329] fs: dcache: Use READ_ONCE when accessing i_dir_seq Date: Mon, 28 May 2018 12:01:12 +0200 Message-Id: <20180528100254.469218830@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180528100241.796630982@linuxfoundation.org> References: <20180528100241.796630982@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Will Deacon [ Upstream commit 8cc07c808c9d595e81cbe5aad419b7769eb2e5c9 ] i_dir_seq is subject to concurrent modification by a cmpxchg or store-release operation, so ensure that the relaxed access in d_alloc_parallel uses READ_ONCE. Reported-by: Peter Zijlstra Signed-off-by: Will Deacon Signed-off-by: Al Viro Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- fs/dcache.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/fs/dcache.c +++ b/fs/dcache.c @@ -2502,7 +2502,7 @@ retry: } hlist_bl_lock(b); - if (unlikely(parent->d_inode->i_dir_seq != seq)) { + if (unlikely(READ_ONCE(parent->d_inode->i_dir_seq) != seq)) { hlist_bl_unlock(b); rcu_read_unlock(); goto retry;