I got report about that sometimes the WARN_ON occurs there which should
never happen. I came to the conclusion that the mac header is there but
inside the headroom of skb. The skb->len information doesn't contain the
information about the headroom length and skb->len is lesser than two.
We check now if the skb_mac_header pointer is set and the room between
mac header pointer and tail pointer.
Signed-off-by: Alexander Aring <aar@xxxxxxxxxxxxxx>
---
include/net/mac802154.h | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/include/net/mac802154.h b/include/net/mac802154.h
index da574bb..2e3cdd20 100644
--- a/include/net/mac802154.h
+++ b/include/net/mac802154.h
@@ -247,8 +247,9 @@ struct ieee802154_ops {
*/
static inline __le16 ieee802154_get_fc_from_skb(const struct sk_buff *skb)
{
- /* return some invalid fc on failure */
- if (unlikely(skb->len < 2)) {
+ /* check if we can fc at skb_mac_header of sk buffer */
+ if (unlikely(!skb_mac_header_was_set(skb) ||
+ (skb_tail_pointer(skb) - skb_mac_header(skb)) < 2)) {
WARN_ON(1);
return cpu_to_le16(0);
}
--
2.7.1
--
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