From e3f1193c8293731038bdbe98266636ab67f2a162 Mon Sep 17 00:00:00 2001 From: Nikolay Borisov Date: Fri, 16 Oct 2015 09:40:28 +0300 Subject: netfilter: ipset: Fix sleeping memory allocation in atomic context 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") Acked-by: Jozsef Kadlecsik Signed-off-by: Nikolay Borisov Signed-off-by: Jozsef Kadlecsik --- kernel/net/netfilter/ipset/ip_set_list_set.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/net/netfilter/ipset/ip_set_list_set.c b/kernel/net/netfilter/ipset/ip_set_list_set.c index b11ba96..0f9195f 100644 --- a/kernel/net/netfilter/ipset/ip_set_list_set.c +++ b/kernel/net/netfilter/ipset/ip_set_list_set.c @@ -298,7 +298,7 @@ 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; -- cgit v1.2.3