commit 5a8e7aea953bdb6d4da13aff6f1e7f9c62023499
author Cong Wang <xiyou.wangcong@gmail.com> Thu Oct 11 11:15:13 2018 -0700
committer David S. Miller <davem@davemloft.net> Mon Oct 15 22:01:37 2018 -0700
tree eadd98d8a321daa8892ba298d62000ed3eb86fca
parent d0f068e5720ac4eea13e184bb7526848f189f909

llc: set SOCK_RCU_FREE in llc_sap_add_socket()

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().

Reported-by: syzbot+11e05f04c15e03be5254@syzkaller.appspotmail.com
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>