From: NeilBrown <neilb@xxxxxxx>
[ 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 <neilb@xxxxxxx>
Signed-off-by: Anna Schumaker <Anna.Schumaker@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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 8f309bcdf84fe..0c28280dd3bcb 100644
--- a/net/sunrpc/sysfs.c
+++ b/net/sunrpc/sysfs.c
@@ -115,11 +115,14 @@ static ssize_t rpc_sysfs_xprt_srcaddr_show(struct kobject *kobj,
}
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 d8ee06a9650a1..03770e56df361 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -1641,7 +1641,12 @@ 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);
--
2.34.1
