[PATCH 6.1 165/473] net: usb: sr9700: stop lying about skb->truesize

Greg Kroah-Hartman
2024-06-06T14:14:49Z

From: Eric Dumazet <edumazet@google.com>

[ Upstream commit 05417aa9c0c038da2464a0c504b9d4f99814a23b ]

Some usb drivers 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")

Fixes: c9b37458e956 ("USB2NET : SR9700 : One chip USB 1.1 USB2NET SR9700Device Driver Support")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20240506143939.3673865-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/usb/sr9700.c | 10 +++-------
1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/drivers/net/usb/sr9700.c b/drivers/net/usb/sr9700.c
index 3164451e1010c..0a662e42ed965 100644
--- a/drivers/net/usb/sr9700.c
+++ b/drivers/net/usb/sr9700.c
@@ -421,19 +421,15 @@ static int sr9700_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
skb_pull(skb, 3);
skb->len = len;
skb_set_tail_pointer(skb, len);
- skb->truesize = len + sizeof(struct sk_buff);
return 2;
}

- /* skb_clone is used for address align */
- sr_skb = skb_clone(skb, GFP_ATOMIC);
+ sr_skb = netdev_alloc_skb_ip_align(dev->net, len);
if (!sr_skb)
return 0;

- sr_skb->len = len;
- sr_skb->data = skb->data + 3;
- skb_set_tail_pointer(sr_skb, len);
- sr_skb->truesize = len + sizeof(struct sk_buff);
+ skb_put(sr_skb, len);
+ memcpy(sr_skb->data, skb->data + 3, len);
usbnet_skb_return(dev, sr_skb);

skb_pull(skb, len + SR_RX_OVERHEAD);
--
2.43.0