[PATCH] net: wwan: iosm: fix potential skb leak in MUX DL decode

[Fang Xieyan]

ipc_mux_dl_decode() owns the received skb and frees it after
decoding. However, the early return when skb->data is NULL
bypasses the skb cleanup.

Free the skb through ipc_pcie_kfree_skb() before returning
to ensure that both the DMA mapping and skb are released.

Fixes: 3670970dd8c6 ("net: iosm: shared memory IPC interface")
Reviewed-by: Guanglei Zhu <zhugl3@xxxxxxxxxxxx>
Signed-off-by: Fang Xieyan <fangxy@xxxxxxxxxxxx>
---
 drivers/net/wwan/iosm/iosm_ipc_mux_codec.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wwan/iosm/iosm_ipc_mux_codec.c b/drivers/net/wwan/iosm/iosm_ipc_mux_codec.c
index 0bbd41263cc2..61700688eac9 100644
--- a/drivers/net/wwan/iosm/iosm_ipc_mux_codec.c
+++ b/drivers/net/wwan/iosm/iosm_ipc_mux_codec.c
@@ -693,8 +693,10 @@ void ipc_mux_dl_decode(struct iosm_mux *ipc_mux, struct sk_buff *skb)
 {
 	u32 signature;
 
-	if (!skb->data)
+	if (!skb->data) {
+		ipc_pcie_kfree_skb(ipc_mux->pcie, skb);
 		return;
+	}
 
 	/* Decode the MUX header type. */
 	signature = le32_to_cpup((__le32 *)skb->data);
-- 
2.50.1