From: Nikolay Borisov <kernel@xxxxxxxx>
Commit 00590fdd5be0 introduced RCU locking in list type and in
doing so introduced a memory allocation in list_set_add, which
is done in an atomic context, due to the fact that ipset rcu
list modifications are serialised with a spin lock. The reason
why we can't use a mutex is that in addition to modifying the
list with ipset commands, it's also being modified when a
particular ipset rule timeout expires aka garbage collection.
This gc is triggered from set_cleanup_entries, which in turn
is invoked from a timer thus requiring the lock to be bh-safe.
Concretely the following call chain can lead to "sleeping function
called in atomic context" splat:
call_ad -> list_set_uadt -> list_set_uadd -> kzalloc(, GFP_KERNEL).
And since GFP_KERNEL allows initiating direct reclaim thus
potentially sleeping in the allocation path.
To fix the issue change the allocation type to GFP_ATOMIC, to
correctly reflect that it is occuring in an atomic context.
Fixes: 00590fdd5be0 ("netfilter: ipset: Introduce RCU locking in list type")
Signed-off-by: Nikolay Borisov <kernel@xxxxxxxx>
Acked-by: Jozsef Kadlecsik <kadlec@xxxxxxxxxxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
net/netfilter/ipset/ip_set_list_set.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/netfilter/ipset/ip_set_list_set.c b/net/netfilter/ipset/ip_set_list_set.c
index a1fe537..5a30ce6 100644
--- a/net/netfilter/ipset/ip_set_list_set.c
+++ b/net/netfilter/ipset/ip_set_list_set.c
@@ -297,7 +297,7 @@ list_set_uadd(struct ip_set *set, void *value, const struct ip_set_ext *ext,
ip_set_timeout_expired(ext_timeout(n, set))))
n = NULL;
- e = kzalloc(set->dsize, GFP_KERNEL);
+ e = kzalloc(set->dsize, GFP_ATOMIC);
if (!e)
return -ENOMEM;
e->id = d->id;
--
2.1.4
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