From fdc42287ae3f8a35cc2098307f52d7864b4bc8ed Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Wed, 18 Mar 2026 15:55:51 +0800 Subject: [PATCH] SUNRPC: lock against ->sock changing during sysfs read [ Upstream commit b49ea673e119f59c71645e2f65b3ccad857c90ee ] ->sock can be set to NULL asynchronously unless ->recv_mutex is held. So it is important to hold that mutex. Otherwise a sysfs read can trigger an oops. Commit 17f09d3f619a ("SUNRPC: Check if the xprt is connected before handling sysfs reads") appears to attempt to fix this problem, but it only narrows the race window. Fixes: 17f09d3f619a ("SUNRPC: Check if the xprt is connected before handling sysfs reads") Fixes: a8482488a7d6 ("SUNRPC query transport's source port") Signed-off-by: NeilBrown Signed-off-by: Anna Schumaker Signed-off-by: Robert Garcia Signed-off-by: Greg Kroah-Hartman --- net/sunrpc/sysfs.c | 5 ++++- net/sunrpc/xprtsock.c | 7 ++++++- 2 files changed, 10 insertions(+), 2 deletions(-) diff --git a/net/sunrpc/sysfs.c b/net/sunrpc/sysfs.c index 55da1b627a7d..83ba1f2adf62 100644 --- a/net/sunrpc/sysfs.c +++ b/net/sunrpc/sysfs.c @@ -113,11 +113,14 @@ static ssize_t rpc_sysfs_xprt_srcaddr_show(struct kobject *kobj, return 0; sock = container_of(xprt, struct sock_xprt, xprt); - if (kernel_getsockname(sock->sock, (struct sockaddr *)&saddr) < 0) + mutex_lock(&sock->recv_mutex); + if (sock->sock == NULL || + kernel_getsockname(sock->sock, (struct sockaddr *)&saddr) < 0) goto out; ret = sprintf(buf, "%pISc\n", &saddr); out: + mutex_unlock(&sock->recv_mutex); xprt_put(xprt); return ret + 1; } diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c index 9e122c20fcc6..07acc6845ce2 100644 --- a/net/sunrpc/xprtsock.c +++ b/net/sunrpc/xprtsock.c @@ -1680,7 +1680,12 @@ static int xs_get_srcport(struct sock_xprt *transport) unsigned short get_srcport(struct rpc_xprt *xprt) { struct sock_xprt *sock = container_of(xprt, struct sock_xprt, xprt); - return xs_sock_getport(sock->sock); + unsigned short ret = 0; + mutex_lock(&sock->recv_mutex); + if (sock->sock) + ret = xs_sock_getport(sock->sock); + mutex_unlock(&sock->recv_mutex); + return ret; } EXPORT_SYMBOL(get_srcport);