From patchwork Tue Jan 24 22:04:10 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Miller X-Patchwork-Id: 137659 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id CA385B6F65 for ; Wed, 25 Jan 2012 09:04:20 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751735Ab2AXWET (ORCPT ); Tue, 24 Jan 2012 17:04:19 -0500 Received: from shards.monkeyblade.net ([198.137.202.13]:42466 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751700Ab2AXWER (ORCPT ); Tue, 24 Jan 2012 17:04:17 -0500 Received: from localhost (nat-pool-rdu.redhat.com [66.187.233.202]) (authenticated bits=0) by shards.monkeyblade.net (8.14.4/8.14.4) with ESMTP id q0OM4BvB006752 (version=TLSv1/SSLv3 cipher=RC4-SHA bits=128 verify=NO); Tue, 24 Jan 2012 14:04:12 -0800 Date: Tue, 24 Jan 2012 17:04:10 -0500 (EST) Message-Id: <20120124.170410.829129930720684609.davem@davemloft.net> To: jwboyer@gmail.com Cc: venkat.x.venkatsubra@oracle.com, netdev@vger.kernel.org Subject: Re: Backtrace in rds code From: David Miller In-Reply-To: References: X-Mailer: Mew version 6.4 on Emacs 23.3 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.2.6 (shards.monkeyblade.net [198.137.202.13]); Tue, 24 Jan 2012 14:04:13 -0800 (PST) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Please try this patch: -------------------- rds: Make rds_sock_lock BH rather than IRQ safe. rds_sock_info() triggers locking warnings because we try to perform a local_bh_enable() (via sock_i_ino()) while hardware interrupts are disabled (via taking rds_sock_lock). There is no reason for rds_sock_lock to be a hardware IRQ disabling lock, none of these access paths run in hardware interrupt context. Therefore making it a BH disabling lock is safe and sufficient to fix this bug. Reported-by: Kumar Sanghvi Reported-by: Josh Boyer Signed-off-by: David S. Miller --- net/rds/af_rds.c | 20 ++++++++------------ 1 files changed, 8 insertions(+), 12 deletions(-) diff --git a/net/rds/af_rds.c b/net/rds/af_rds.c index bb6ad81..424ff62 100644 --- a/net/rds/af_rds.c +++ b/net/rds/af_rds.c @@ -68,7 +68,6 @@ static int rds_release(struct socket *sock) { struct sock *sk = sock->sk; struct rds_sock *rs; - unsigned long flags; if (!sk) goto out; @@ -94,10 +93,10 @@ static int rds_release(struct socket *sock) rds_rdma_drop_keys(rs); rds_notify_queue_get(rs, NULL); - spin_lock_irqsave(&rds_sock_lock, flags); + spin_lock_bh(&rds_sock_lock); list_del_init(&rs->rs_item); rds_sock_count--; - spin_unlock_irqrestore(&rds_sock_lock, flags); + spin_unlock_bh(&rds_sock_lock); rds_trans_put(rs->rs_transport); @@ -409,7 +408,6 @@ static const struct proto_ops rds_proto_ops = { static int __rds_create(struct socket *sock, struct sock *sk, int protocol) { - unsigned long flags; struct rds_sock *rs; sock_init_data(sock, sk); @@ -426,10 +424,10 @@ static int __rds_create(struct socket *sock, struct sock *sk, int protocol) spin_lock_init(&rs->rs_rdma_lock); rs->rs_rdma_keys = RB_ROOT; - spin_lock_irqsave(&rds_sock_lock, flags); + spin_lock_bh(&rds_sock_lock); list_add_tail(&rs->rs_item, &rds_sock_list); rds_sock_count++; - spin_unlock_irqrestore(&rds_sock_lock, flags); + spin_unlock_bh(&rds_sock_lock); return 0; } @@ -471,12 +469,11 @@ static void rds_sock_inc_info(struct socket *sock, unsigned int len, { struct rds_sock *rs; struct rds_incoming *inc; - unsigned long flags; unsigned int total = 0; len /= sizeof(struct rds_info_message); - spin_lock_irqsave(&rds_sock_lock, flags); + spin_lock_bh(&rds_sock_lock); list_for_each_entry(rs, &rds_sock_list, rs_item) { read_lock(&rs->rs_recv_lock); @@ -492,7 +489,7 @@ static void rds_sock_inc_info(struct socket *sock, unsigned int len, read_unlock(&rs->rs_recv_lock); } - spin_unlock_irqrestore(&rds_sock_lock, flags); + spin_unlock_bh(&rds_sock_lock); lens->nr = total; lens->each = sizeof(struct rds_info_message); @@ -504,11 +501,10 @@ static void rds_sock_info(struct socket *sock, unsigned int len, { struct rds_info_socket sinfo; struct rds_sock *rs; - unsigned long flags; len /= sizeof(struct rds_info_socket); - spin_lock_irqsave(&rds_sock_lock, flags); + spin_lock_bh(&rds_sock_lock); if (len < rds_sock_count) goto out; @@ -529,7 +525,7 @@ out: lens->nr = rds_sock_count; lens->each = sizeof(struct rds_info_socket); - spin_unlock_irqrestore(&rds_sock_lock, flags); + spin_unlock_bh(&rds_sock_lock); } static void rds_exit(void)