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 <tatsu@xxxxxxxxxxxxx> --- 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 -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
