xfrm: policy: increment xfrm_hash_generation on hash rebuild

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Hash rebuild will re-set all the inexact entries, then re-insert them.
Lookups that can occur in parallel will therefore not find any policies.

This was safe when lookups were still guarded by rwlock.
After rcu-ification, lookups check the hash_generation seqcount to detect
when a hash resize takes place.  Hash rebuild missed the needed increment.

Hash resizes and hash rebuilds cannot occur in parallel (both acquire
hash_resize_mutex), so just increment xfrm_hash_generation, like resize.

Fixes: a7c44247f7 ("xfrm: policy: make xfrm_policy_lookup_bytype lockless")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

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Florian Westphal 2019-01-04 14:17:01 +01:00 • committed by Steffen Klassert

parent 355b00d1e1

commit 7a474c3658

1 changed files with 2 additions and 0 deletions

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net/xfrm/xfrm_policy.c

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