A null check is needed after all. netlink skbs can have skb->head be
backed by vmalloc. The netlink destructor vfree()s head, then sets it to
NULL. We then panic in skb_release_data with a NULL dereference.
Re-add such a test.
Alternative would be to switch to kvfree to free skb->head memory
and remove the special handling in netlink destructor.
Reported-by: kernel test robot <fengguang...@intel.com>
Fixes: 06dc75ab06943 ("net: Revert "net: add function to allocate sk_buff head
without data area")
Signed-off-by: Florian Westphal <f...@strlen.de>
---
net/core/skbuff.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 84bdfa2..c27da51 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -638,7 +638,8 @@ void skb_release_head_state(struct sk_buff *skb)
static void skb_release_all(struct sk_buff *skb)
{
skb_release_head_state(skb);
- skb_release_data(skb);
+ if (likely(skb->head))
+ skb_release_data(skb);
}
/**
--
1.8.3.1
