[PATCH] net: wwan: t7xx: check skb_clone in control TX

[Ruoyu Wang <ruoyuw560@gmail.com>]

t7xx_port_ctrl_tx() clones each skb fragment before passing it to the
port transmit path. The clone is used immediately to set cloned->len, so
an skb_clone() failure results in a NULL pointer dereference.

Check the clone before using it. If previous fragments were already
queued, preserve the driver's existing partial-write behavior by
returning the number of bytes submitted so far. Keep the existing byte
accounting unchanged so this patch only handles the allocation failure.

Signed-off-by: Ruoyu Wang <ruoyuw560@gmail.com>
---
 drivers/net/wwan/t7xx/t7xx_port_wwan.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/wwan/t7xx/t7xx_port_wwan.c b/drivers/net/wwan/t7xx/t7xx_port_wwan.c
index 7fc569565..d2529df75 100644
--- a/drivers/net/wwan/t7xx/t7xx_port_wwan.c
+++ b/drivers/net/wwan/t7xx/t7xx_port_wwan.c
@@ -106,6 +106,8 @@ static int t7xx_port_ctrl_tx(struct t7xx_port *port, struct sk_buff *skb)
 
 	while (cur) {
 		cloned = skb_clone(cur, GFP_KERNEL);
+		if (!cloned)
+			return cnt ? cnt : -ENOMEM;
 		cloned->len = skb_headlen(cur);
 		ret = t7xx_port_send_skb(port, cloned, 0, 0);
 		if (ret) {
-- 
2.51.0