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| author | Steffen Klassert <steffen.klassert@secunet.com> | 2021-07-02 10:20:22 +0300 |
|---|---|---|
| committer | Steffen Klassert <steffen.klassert@secunet.com> | 2021-07-02 10:20:22 +0300 |
| commit | eaf228263921cd15962654b539d916380a0f076e (patch) | |
| tree | b97867b047965e8ca0c2b3c5b7386986918f7486 | |
| parent | 7c1a80e80cde008f271bae630d28cf684351e807 (diff) | |
| download | linux-eaf228263921cd15962654b539d916380a0f076e.tar.xz | |
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>
| -rw-r--r-- | net/xfrm/xfrm_policy.c | 21 |
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(); |