summaryrefslogtreecommitdiff
path: root/net/xfrm
diff options
context:
space:
mode:
authorSteffen Klassert <steffen.klassert@secunet.com>2021-07-02 09:20:22 +0200
committerSteffen Klassert <steffen.klassert@secunet.com>2021-07-02 09:20:22 +0200
commiteaf228263921cd15962654b539d916380a0f076e (patch)
treeb97867b047965e8ca0c2b3c5b7386986918f7486 /net/xfrm
parent7c1a80e80cde008f271bae630d28cf684351e807 (diff)
Revert "xfrm: policy: Read seqcount outside of rcu-read side in xfrm_policy_lookup_bytype"
This reverts commit d7b0408934c749f546b01f2b33d07421a49b6f3e. This commit tried to fix a locking bug introduced by commit 77cc278f7b20 ("xfrm: policy: Use sequence counters with associated lock"). As it turned out, this patch did not really fix the bug. A proper fix for this bug is applied on top of this revert. Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Diffstat (limited to 'net/xfrm')
-rw-r--r--net/xfrm/xfrm_policy.c21
1 files changed, 7 insertions, 14 deletions
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index e9d0df2a2ab1..ce500f847b99 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -2092,15 +2092,12 @@ static struct xfrm_policy *xfrm_policy_lookup_bytype(struct net *net, u8 type,
if (unlikely(!daddr || !saddr))
return NULL;
- retry:
- sequence = read_seqcount_begin(&xfrm_policy_hash_generation);
rcu_read_lock();
-
- chain = policy_hash_direct(net, daddr, saddr, family, dir);
- if (read_seqcount_retry(&xfrm_policy_hash_generation, sequence)) {
- rcu_read_unlock();
- goto retry;
- }
+ retry:
+ do {
+ sequence = read_seqcount_begin(&xfrm_policy_hash_generation);
+ chain = policy_hash_direct(net, daddr, saddr, family, dir);
+ } while (read_seqcount_retry(&xfrm_policy_hash_generation, sequence));
ret = NULL;
hlist_for_each_entry_rcu(pol, chain, bydst) {
@@ -2131,15 +2128,11 @@ static struct xfrm_policy *xfrm_policy_lookup_bytype(struct net *net, u8 type,
}
skip_inexact:
- if (read_seqcount_retry(&xfrm_policy_hash_generation, sequence)) {
- rcu_read_unlock();
+ if (read_seqcount_retry(&xfrm_policy_hash_generation, sequence))
goto retry;
- }
- if (ret && !xfrm_pol_hold_rcu(ret)) {
- rcu_read_unlock();
+ if (ret && !xfrm_pol_hold_rcu(ret))
goto retry;
- }
fail:
rcu_read_unlock();