netfilter: ipset: Fix sleeping memory allocation in atomic context
commit 00db674b upstream. Commit 00590fdd 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: 00590fdd ("netfilter: ipset: Introduce RCU locking in list type") Signed-off-by: Nikolay Borisov <kernel@kyup.com> Acked-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Showing
Please register or sign in to comment