diff options
| author | Cong Wang <xiyou.wangcong@gmail.com> | 2018-08-07 12:41:38 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-08-22 07:47:13 +0200 |
| commit | 2ff9f0820ddaad35bb2bca35b98f019a3b264d37 (patch) | |
| tree | a5844ca3f24f68f2fd6a8d2ca21d07d6c83b6e9a /include | |
| parent | ae7d506b72db2f7c1e37233fecd05393767e2dcb (diff) | |
llc: use refcount_inc_not_zero() for llc_sap_find()
[ Upstream commit 0dcb82254d65f72333aa50ad626d1e9665ad093b ]
llc_sap_put() decreases the refcnt before deleting sap
from the global list. Therefore, there is a chance
llc_sap_find() could find a sap with zero refcnt
in this global list.
Close this race condition by checking if refcnt is zero
or not in llc_sap_find(), if it is zero then it is being
removed so we can just treat it as gone.
Reported-by: <syzbot+278893f3f7803871f7ce@syzkaller.appspotmail.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/net/llc.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/include/net/llc.h b/include/net/llc.h index e8e61d4fb458..82d989995d18 100644 --- a/include/net/llc.h +++ b/include/net/llc.h @@ -116,6 +116,11 @@ static inline void llc_sap_hold(struct llc_sap *sap) atomic_inc(&sap->refcnt); } +static inline bool llc_sap_hold_safe(struct llc_sap *sap) +{ + return atomic_inc_not_zero(&sap->refcnt); +} + void llc_sap_close(struct llc_sap *sap); static inline void llc_sap_put(struct llc_sap *sap) |