From 1b3b2d9e772b99ea3d0f1f2252bf7a1c94b88be6 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Mon, 6 May 2024 14:23:58 +0000 Subject: net: usb: smsc75xx: stop lying about skb->truesize Some usb drivers try to set small skb->truesize and break core networking stacks. In this patch, I removed one of the skb->truesize override. I also replaced one skb_clone() by an allocation of a fresh and small skb, to get minimally sized skbs, like we did in commit 1e2c61172342 ("net: cdc_ncm: reduce skb truesize in rx path") and 4ce62d5b2f7a ("net: usb: ax88179_178a: stop lying about skb->truesize") Signed-off-by: Eric Dumazet Cc: Steve Glendinning Link: https://lore.kernel.org/r/20240506142358.3657918-1-edumazet@google.com Signed-off-by: Jakub Kicinski --- drivers/net/usb/smsc75xx.c | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-) diff --git a/drivers/net/usb/smsc75xx.c b/drivers/net/usb/smsc75xx.c index 78ad2da3ee29..0726e18bee6f 100644 --- a/drivers/net/usb/smsc75xx.c +++ b/drivers/net/usb/smsc75xx.c @@ -2234,27 +2234,23 @@ static int smsc75xx_rx_fixup(struct usbnet *dev, struct sk_buff *skb) rx_cmd_b); skb_trim(skb, skb->len - 4); /* remove fcs */ - skb->truesize = size + sizeof(struct sk_buff); return 1; } - ax_skb = skb_clone(skb, GFP_ATOMIC); + /* Use "size - 4" to remove fcs */ + ax_skb = netdev_alloc_skb_ip_align(dev->net, size - 4); if (unlikely(!ax_skb)) { netdev_warn(dev->net, "Error allocating skb\n"); return 0; } - ax_skb->len = size; - ax_skb->data = packet; - skb_set_tail_pointer(ax_skb, size); + skb_put(ax_skb, size - 4); + memcpy(ax_skb->data, packet, size - 4); smsc75xx_rx_csum_offload(dev, ax_skb, rx_cmd_a, rx_cmd_b); - skb_trim(ax_skb, ax_skb->len - 4); /* remove fcs */ - ax_skb->truesize = size + sizeof(struct sk_buff); - usbnet_skb_return(dev, ax_skb); } -- cgit v1.2.3-70-g09d2