From: Benjamin Coddington bcodding@redhat.com
[ Upstream commit af84537dbd1b39505d1f3d8023029b4a59666513 ]
Since commit 4f8943f80883 ("SUNRPC: Replace direct task wakeups from softirq context") there has been a race to the value of the sk_err if both XPRT_SOCK_WAKE_ERROR and XPRT_SOCK_WAKE_DISCONNECT are set. In that case, we may end up losing the sk_err value that existed when xs_error_report was called.
Fix this by reverting to the previous behavior: instead of using SO_ERROR to retrieve the value at a later time (which might also return sk_err_soft), copy the sk_err value onto struct sock_xprt, and use that value to wake pending tasks.
Signed-off-by: Benjamin Coddington bcodding@redhat.com Fixes: 4f8943f80883 ("SUNRPC: Replace direct task wakeups from softirq context") Signed-off-by: Anna Schumaker Anna.Schumaker@Netapp.com Signed-off-by: Sasha Levin sashal@kernel.org --- include/linux/sunrpc/xprtsock.h | 1 + net/sunrpc/xprtsock.c | 17 ++++++++--------- 2 files changed, 9 insertions(+), 9 deletions(-)
diff --git a/include/linux/sunrpc/xprtsock.h b/include/linux/sunrpc/xprtsock.h index 7638dbe7bc500..a940de03808dd 100644 --- a/include/linux/sunrpc/xprtsock.h +++ b/include/linux/sunrpc/xprtsock.h @@ -61,6 +61,7 @@ struct sock_xprt { struct mutex recv_mutex; struct sockaddr_storage srcaddr; unsigned short srcport; + int xprt_err;
/* * UDP socket buffer size parameters diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c index e2176c167a579..4e0b5bed6c737 100644 --- a/net/sunrpc/xprtsock.c +++ b/net/sunrpc/xprtsock.c @@ -1243,19 +1243,21 @@ static void xs_error_report(struct sock *sk) { struct sock_xprt *transport; struct rpc_xprt *xprt; - int err;
read_lock_bh(&sk->sk_callback_lock); if (!(xprt = xprt_from_sock(sk))) goto out;
transport = container_of(xprt, struct sock_xprt, xprt); - err = -sk->sk_err; - if (err == 0) + transport->xprt_err = -sk->sk_err; + if (transport->xprt_err == 0) goto out; dprintk("RPC: xs_error_report client %p, error=%d...\n", - xprt, -err); - trace_rpc_socket_error(xprt, sk->sk_socket, err); + xprt, -transport->xprt_err); + trace_rpc_socket_error(xprt, sk->sk_socket, transport->xprt_err); + + /* barrier ensures xprt_err is set before XPRT_SOCK_WAKE_ERROR */ + smp_mb__before_atomic(); xs_run_error_worker(transport, XPRT_SOCK_WAKE_ERROR); out: read_unlock_bh(&sk->sk_callback_lock); @@ -2470,7 +2472,6 @@ static void xs_wake_write(struct sock_xprt *transport) static void xs_wake_error(struct sock_xprt *transport) { int sockerr; - int sockerr_len = sizeof(sockerr);
if (!test_bit(XPRT_SOCK_WAKE_ERROR, &transport->sock_state)) return; @@ -2479,9 +2480,7 @@ static void xs_wake_error(struct sock_xprt *transport) goto out; if (!test_and_clear_bit(XPRT_SOCK_WAKE_ERROR, &transport->sock_state)) goto out; - if (kernel_getsockopt(transport->sock, SOL_SOCKET, SO_ERROR, - (char *)&sockerr, &sockerr_len) != 0) - goto out; + sockerr = xchg(&transport->xprt_err, 0); if (sockerr < 0) xprt_wake_pending_tasks(&transport->xprt, sockerr); out: