Commit fb7e2399 authored by Committed by David S. Miller
[TCP]: skb is unexpectedly freed.
I encountered a kernel panic with my test program, which is a very simple IPv6 client-server program. The server side sets IPV6_RECVPKTINFO on a listening socket, and the client side just sends a message to the server. Then the kernel panic occurs on the server. (If you need the test program, please let me know. I can provide it.) This problem happens because a skb is forcibly freed in tcp_rcv_state_process(). When a socket in listening state(TCP_LISTEN) receives a syn packet, then tcp_v6_conn_request() will be called from tcp_rcv_state_process(). If the tcp_v6_conn_request() successfully returns, the skb would be discarded by __kfree_skb(). However, in case of a listening socket which was already set IPV6_RECVPKTINFO, an address of the skb will be stored in treq->pktopts and a ref count of the skb will be incremented in tcp_v6_conn_request(). But, even if the skb is still in use, the skb will be freed. Then someone still using the freed skb will cause the kernel panic. I suggest to use kfree_skb() instead of __kfree_skb(). Signed-off-by: Masayuki Nakagawa <firstname.lastname@example.org> Signed-off-by: David S. Miller <email@example.com>
Showing with 4 additions and 2 deletions