From 1f428e30947395d9b9aacee03e25a4e6cfcad7a4 Mon Sep 17 00:00:00 2001 From: Yi Cong Date: Wed, 29 Jul 2026 11:04:36 +0800 Subject: [PATCH] net: usb: ax88179_178a: fix skb leak in ax88179_tx_fixup() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When the interface has NETIF_F_SG enabled and skb_linearize() fails in ax88179_tx_fixup(), the function returns NULL without freeing the skb. usbnet_start_xmit() treats a NULL return from tx_fixup() as a drop (info->flags does not set FLAG_MULTI_PACKET for this driver), jumping to the "drop" label where it does `if (skb) dev_kfree_skb_any(skb)`. Because tx_fixup() returned NULL, the local skb variable in usbnet_start_xmit() is NULL, so the original skb is never freed — a memory leak on every TX frame whose linearization fails (i.e. under memory pressure). Free the skb before returning, matching the error handling already used for the pskb_expand_head() failure path in the same function. Fixes: 16b1c4e01c89 ("net: usb: ax88179_178a: add TSO feature") Cc: stable@vger.kernel.org Signed-off-by: Yi Cong Link: https://patch.msgid.link/20260729030436.3420477-1-cong.yi@linux.dev Signed-off-by: Jakub Kicinski --- drivers/net/usb/ax88179_178a.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/net/usb/ax88179_178a.c b/drivers/net/usb/ax88179_178a.c index 98f899ea2e94..81d8412ce8e2 100644 --- a/drivers/net/usb/ax88179_178a.c +++ b/drivers/net/usb/ax88179_178a.c @@ -1487,8 +1487,10 @@ ax88179_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags) headroom = skb_headroom(skb) - 8; - if ((dev->net->features & NETIF_F_SG) && skb_linearize(skb)) + if ((dev->net->features & NETIF_F_SG) && skb_linearize(skb)) { + dev_kfree_skb_any(skb); return NULL; + } if ((skb_header_cloned(skb) || headroom < 0) && pskb_expand_head(skb, headroom < 0 ? 8 : 0, 0, GFP_ATOMIC)) {