[Devel] [PATCH RH76 v2] tcp: sendpage should not handle Slab objects

[Vasily Averin]

According to network guru .sendpage should not handle Slab objects.
The patch helps to detects such incidents, generates warning
and switch processing to safe .sendmsg callback.

v2: properly backported to rhel76 kernel

https://jira.sw.ru/browse/PSBM-90529
Signed-off-by: Vasily Averin <vvs at virtuozo.com>

-------------- next part --------------
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index e74c83789279..dcfaf4ff70e1 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1006,6 +1006,13 @@ int tcp_sendpage(struct sock *sk, struct page *page, int offset,
 		return sock_no_sendpage(sk->sk_socket, page, offset, size,
 					flags);
 
+	if (PageSlab(page)) {
+		WARN_ONCE(true, "sendpage should not handle Slab objects,"
+				" please fix callers\n");
+		return sock_no_sendpage(sk->sk_socket, page, offset, size,
+					flags);
+	}
+
 	lock_sock(sk);
 	res = do_tcp_sendpages(sk, page, offset, size, flags);
 	release_sock(sk);