From: Benjamin Coddington <bcodding@xxxxxxxxxx>
[ 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@xxxxxxxxxx>
Fixes: 4f8943f80883 ("SUNRPC: Replace direct task wakeups from softirq context")
Signed-off-by: Anna Schumaker <Anna.Schumaker@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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:
--
2.20.1
