Return-Path: Received: from TYO201.gate.nec.co.jp ([210.143.35.51]:54848 "EHLO tyo201.gate.nec.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754172AbbJIBoj convert rfc822-to-8bit (ORCPT ); Thu, 8 Oct 2015 21:44:39 -0400 From: Kosuke Tatsukawa To: Trond Myklebust , Anna Schumaker , "J. Bruce Fields" , "Jeff Layton" , "David S. Miller" CC: "linux-nfs@vger.kernel.org" , "netdev@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: [PATCH v2] sunrpc: fix waitqueue_active without memory barrier in sunrpc Date: Fri, 9 Oct 2015 01:44:07 +0000 Message-ID: <17EC94B0A072C34B8DCF0D30AD16044A028748C0@BPXM09GP.gisp.nec.co.jp> Content-Type: text/plain; charset="iso-2022-jp" MIME-Version: 1.0 Sender: linux-nfs-owner@vger.kernel.org List-ID: There are several places in net/sunrpc/svcsock.c which calls waitqueue_active() without calling a memory barrier. Add a memory barrier just as in wq_has_sleeper(). I found this issue when I was looking through the linux source code for places calling waitqueue_active() before wake_up*(), but without preceding memory barriers, after sending a patch to fix a similar issue in drivers/tty/n_tty.c (Details about the original issue can be found here: https://lkml.org/lkml/2015/9/28/849). Signed-off-by: Kosuke Tatsukawa --- v2: - Fixed compiler warnings caused by type mismatch v1: - https://lkml.org/lkml/2015/10/8/993 --- net/sunrpc/svcsock.c | 6 ++++++ 1 files changed, 6 insertions(+), 0 deletions(-) diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c index 0c81202..ec19444 100644 --- a/net/sunrpc/svcsock.c +++ b/net/sunrpc/svcsock.c @@ -414,6 +414,7 @@ static void svc_udp_data_ready(struct sock *sk) set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags); svc_xprt_enqueue(&svsk->sk_xprt); } + smp_mb(); if (wq && waitqueue_active(wq)) wake_up_interruptible(wq); } @@ -432,6 +433,7 @@ static void svc_write_space(struct sock *sk) svc_xprt_enqueue(&svsk->sk_xprt); } + smp_mb(); if (wq && waitqueue_active(wq)) { dprintk("RPC svc_write_space: someone sleeping on %p\n", svsk); @@ -787,6 +789,7 @@ static void svc_tcp_listen_data_ready(struct sock *sk) } wq = sk_sleep(sk); + smp_mb(); if (wq && waitqueue_active(wq)) wake_up_interruptible_all(wq); } @@ -808,6 +811,7 @@ static void svc_tcp_state_change(struct sock *sk) set_bit(XPT_CLOSE, &svsk->sk_xprt.xpt_flags); svc_xprt_enqueue(&svsk->sk_xprt); } + smp_mb(); if (wq && waitqueue_active(wq)) wake_up_interruptible_all(wq); } @@ -823,6 +827,7 @@ static void svc_tcp_data_ready(struct sock *sk) set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags); svc_xprt_enqueue(&svsk->sk_xprt); } + smp_mb(); if (wq && waitqueue_active(wq)) wake_up_interruptible(wq); } @@ -1594,6 +1599,7 @@ static void svc_sock_detach(struct svc_xprt *xprt) sk->sk_write_space = svsk->sk_owspace; wq = sk_sleep(sk); + smp_mb(); if (wq && waitqueue_active(wq)) wake_up_interruptible(wq); } -- 1.7.1