[PATCH net-next v2 13/15] xen-netfront: don't BUG() when skb_copy_bits() fails in bounce_skb()

[Josef Bacik <josef@xxxxxxxxxxxxxx>]

bounce_skb() is an open-coded skb_copy() for skbs whose data isn't
page-aligned, and it has the same BUG_ON(skb_copy_bits()).
skb_copy_bits() only fails when the skb's lengths don't add up.

bounce_skb() already frees the new skb and returns NULL when the
allocation comes back misaligned, and xennet_start_xmit() drops the
packet in that case.  Take the same path, with a
DEBUG_NET_WARN_ON_ONCE() for debug kernels.

Assisted-by: LLM
Signed-off-by: Josef Bacik <josef@xxxxxxxxxxxxxx>
---
 drivers/net/xen-netfront.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index fdcb91042f29..17811d81937c 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -695,7 +695,12 @@ static struct sk_buff *bounce_skb(const struct sk_buff 
*skb)
        /* Set the tail pointer and length */
        skb_put(n, skb->len);
 
-       BUG_ON(skb_copy_bits(skb, -headerlen, n->head, headerlen + skb->len));
+       if (unlikely(skb_copy_bits(skb, -headerlen, n->head,
+                                  headerlen + skb->len))) {
+               DEBUG_NET_WARN_ON_ONCE(1);
+               kfree_skb(n);
+               return NULL;
+       }
 
        skb_copy_header(n, skb);
        return n;

-- 
2.55.0