1 files changed, 31 insertions, 23 deletions

diff --git a/net/kcm/kcmsock.c b/net/kcm/kcmsock.c
index 7e08a4d3d77d..31762f76cdb5 100644
--- a/net/kcm/kcmsock.c
+++ b/net/kcm/kcmsock.c
@@ -24,6 +24,8 @@
 #include <linux/uaccess.h>
 #include <linux/workqueue.h>
 #include <linux/syscalls.h>
+#include <linux/sched/signal.h>
+
 #include <net/kcm.h>
 #include <net/netns/generic.h>
 #include <net/sock.h>
@@ -929,23 +931,25 @@ static int kcm_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
 			goto out_error;
 	}
 
-	/* New message, alloc head skb */
-	head = alloc_skb(0, sk->sk_allocation);
-	while (!head) {
-		kcm_push(kcm);
-		err = sk_stream_wait_memory(sk, &timeo);
-		if (err)
-			goto out_error;
-
+	if (msg_data_left(msg)) {
+		/* New message, alloc head skb */
 		head = alloc_skb(0, sk->sk_allocation);
-	}
+		while (!head) {
+			kcm_push(kcm);
+			err = sk_stream_wait_memory(sk, &timeo);
+			if (err)
+				goto out_error;
+
+			head = alloc_skb(0, sk->sk_allocation);
+		}
 
-	skb = head;
+		skb = head;
 
-	/* Set ip_summed to CHECKSUM_UNNECESSARY to avoid calling
-	 * csum_and_copy_from_iter from skb_do_copy_data_nocache.
-	 */
-	skb->ip_summed = CHECKSUM_UNNECESSARY;
+		/* Set ip_summed to CHECKSUM_UNNECESSARY to avoid calling
+		 * csum_and_copy_from_iter from skb_do_copy_data_nocache.
+		 */
+		skb->ip_summed = CHECKSUM_UNNECESSARY;
+	}
 
 start:
 	while (msg_data_left(msg)) {
@@ -1018,10 +1022,12 @@ wait_for_memory:
 	if (eor) {
 		bool not_busy = skb_queue_empty(&sk->sk_write_queue);
 
-		/* Message complete, queue it on send buffer */
-		__skb_queue_tail(&sk->sk_write_queue, head);
-		kcm->seq_skb = NULL;
-		KCM_STATS_INCR(kcm->stats.tx_msgs);
+		if (head) {
+			/* Message complete, queue it on send buffer */
+			__skb_queue_tail(&sk->sk_write_queue, head);
+			kcm->seq_skb = NULL;
+			KCM_STATS_INCR(kcm->stats.tx_msgs);
+		}
 
 		if (msg->msg_flags & MSG_BATCH) {
 			kcm->tx_wait_more = true;
@@ -1040,8 +1046,10 @@ wait_for_memory:
 	} else {
 		/* Message not complete, save state */
 partial_message:
-		kcm->seq_skb = head;
-		kcm_tx_msg(head)->last_skb = skb;
+		if (head) {
+			kcm->seq_skb = head;
+			kcm_tx_msg(head)->last_skb = skb;
+		}
 	}
 
 	KCM_STATS_ADD(kcm->stats.tx_bytes, copied);
@@ -1679,7 +1687,7 @@ static int kcm_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
 		struct kcm_attach info;
 
 		if (copy_from_user(&info, (void __user *)arg, sizeof(info)))
-			err = -EFAULT;
+			return -EFAULT;
 
 		err = kcm_attach_ioctl(sock, &info);
 
@@ -1689,7 +1697,7 @@ static int kcm_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
 		struct kcm_unattach info;
 
 		if (copy_from_user(&info, (void __user *)arg, sizeof(info)))
-			err = -EFAULT;
+			return -EFAULT;
 
 		err = kcm_unattach_ioctl(sock, &info);
 
@@ -1700,7 +1708,7 @@ static int kcm_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
 		struct socket *newsock = NULL;
 
 		if (copy_from_user(&info, (void __user *)arg, sizeof(info)))
-			err = -EFAULT;
+			return -EFAULT;
 
 		err = kcm_clone(sock, &info, &newsock);