diff options
| author |   Cong Wang <xiyou.wangcong@gmail.com> | 2018-08-07 12:41:38 -0700 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2018-08-07 15:54:00 -0700 |
| commit | 0dcb82254d65f72333aa50ad626d1e9665ad093b (patch) | |
| tree | 0624bb5c365884b956d4abaf79d50e87a1406762 /include/net/llc.h | |
| parent | dccp: fix undefined behavior with 'cwnd' shift in ccid2_cwnd_restart() (diff) | |
| download | linux-dev-0dcb82254d65f72333aa50ad626d1e9665ad093b.tar.xz linux-dev-0dcb82254d65f72333aa50ad626d1e9665ad093b.zip | |
llc: use refcount_inc_not_zero() for llc_sap_find()
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>
Diffstat (limited to 'include/net/llc.h')
| -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 dc35f25eb679..890a87318014 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) refcount_inc(&sap->refcnt); } +static inline bool llc_sap_hold_safe(struct llc_sap *sap) +{ + return refcount_inc_not_zero(&sap->refcnt); +} + void llc_sap_close(struct llc_sap *sap); static inline void llc_sap_put(struct llc_sap *sap) |