[PATCH 4.9 138/171] llc: set SOCK_RCU_FREE in llc_sap_add_socket()
- Date: Thu, 8 Nov 2018 13:51:48 -0800
- From: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
- Subject: [PATCH 4.9 138/171] llc: set SOCK_RCU_FREE in llc_sap_add_socket()
4.9-stable review patch. If anyone has any objections, please let me know.
From: Cong Wang <xiyou.wangcong@xxxxxxxxx>
[ Upstream commit 5a8e7aea953bdb6d4da13aff6f1e7f9c62023499 ]
WHen an llc sock is added into the sk_laddr_hash of an llc_sap,
it is not marked with SOCK_RCU_FREE.
This causes that the sock could be freed while it is still being
read by __llc_lookup_established() with RCU read lock. sock is
refcounted, but with RCU read lock, nothing prevents the readers
getting a zero refcnt.
Fix it by setting SOCK_RCU_FREE in llc_sap_add_socket().
Signed-off-by: Cong Wang <xiyou.wangcong@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
net/llc/llc_conn.c | 1 +
1 file changed, 1 insertion(+)
@@ -734,6 +734,7 @@ void llc_sap_add_socket(struct llc_sap *
llc_sk(sk)->sap = sap;
+ sock_set_flag(sk, SOCK_RCU_FREE);