diff options
| author |   Florian Westphal <fw@strlen.de> | 2016-08-11 15:17:55 +0200 |
|---|---|---|
| committer |   Steffen Klassert <steffen.klassert@secunet.com> | 2016-08-12 08:07:11 +0200 |
| commit | e37cc8ade5afaf082f804c6d18eb23377146bec4 (patch) | |
| tree | c9e1bf67bfedc04fb6e0b6840bd280198c300549 /net/xfrm | |
| parent | xfrm: policy: add sequence count to sync with hash resize (diff) | |
| download | wireguard-linux-e37cc8ade5afaf082f804c6d18eb23377146bec4.tar.xz wireguard-linux-e37cc8ade5afaf082f804c6d18eb23377146bec4.zip | |
xfrm: policy: use atomic_inc_not_zero in rcu section
If we don't hold the policy lock anymore the refcnt might
already be 0, i.e. policy struct is about to be free'd.
Switch to atomic_inc_not_zero to avoid this.
On removal policies are already unlinked from the tables (lists)
before the last _put occurs so we are not supposed to find the same
'dead' entry on the next loop, so its safe to just repeat the lookup.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Diffstat (limited to 'net/xfrm')
| -rw-r--r-- | net/xfrm/xfrm_policy.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c index 576d90321068..09f2e2b38246 100644 --- a/net/xfrm/xfrm_policy.c +++ b/net/xfrm/xfrm_policy.c @@ -60,6 +60,11 @@ static void __xfrm_policy_link(struct xfrm_policy *pol, int dir); static struct xfrm_policy *__xfrm_policy_unlink(struct xfrm_policy *pol, int dir); +static inline bool xfrm_pol_hold_rcu(struct xfrm_policy *policy) +{ + return atomic_inc_not_zero(&policy->refcnt); +} + static inline bool __xfrm4_selector_match(const struct xfrm_selector *sel, const struct flowi *fl) { @@ -1164,7 +1169,8 @@ static struct xfrm_policy *xfrm_policy_lookup_bytype(struct net *net, u8 type, if (read_seqcount_retry(&xfrm_policy_hash_generation, sequence)) goto retry; - xfrm_pol_hold(ret); + if (ret && !xfrm_pol_hold_rcu(ret)) + goto retry; fail: read_unlock_bh(&net->xfrm.xfrm_policy_lock); |