[NET]: Warn in __skb_trim if skb is paged
It's better to warn and fail rather than rarely triggering BUG on paths
that incorrectly call skb_trim/__skb_trim on a non-linear skb.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 830f58f..93e4db2 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -975,15 +975,16 @@
#define NET_SKB_PAD 16
#endif
-extern int ___pskb_trim(struct sk_buff *skb, unsigned int len, int realloc);
+extern int ___pskb_trim(struct sk_buff *skb, unsigned int len);
static inline void __skb_trim(struct sk_buff *skb, unsigned int len)
{
- if (!skb->data_len) {
- skb->len = len;
- skb->tail = skb->data + len;
- } else
- ___pskb_trim(skb, len, 0);
+ if (unlikely(skb->data_len)) {
+ WARN_ON(1);
+ return;
+ }
+ skb->len = len;
+ skb->tail = skb->data + len;
}
/**
@@ -993,6 +994,7 @@
*
* Cut the length of a buffer down by removing data from the tail. If
* the buffer is already under the length specified it is not modified.
+ * The skb must be linear.
*/
static inline void skb_trim(struct sk_buff *skb, unsigned int len)
{
@@ -1003,12 +1005,10 @@
static inline int __pskb_trim(struct sk_buff *skb, unsigned int len)
{
- if (!skb->data_len) {
- skb->len = len;
- skb->tail = skb->data+len;
- return 0;
- }
- return ___pskb_trim(skb, len, 1);
+ if (skb->data_len)
+ return ___pskb_trim(skb, len);
+ __skb_trim(skb, len);
+ return 0;
}
static inline int pskb_trim(struct sk_buff *skb, unsigned int len)