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Date: Fri, 16 Oct 2015 13:58:55 +0200 (CEST) From: Jozsef Kadlecsik <kadlec@...ckhole.kfki.hu> To: Nikolay Borisov <kernel@...p.com> cc: eric.dumazet@...il.com, netfilter-devel@...r.kernel.org, Pablo Neira Ayuso <pablo@...filter.org>, David Miller <davem@...emloft.net>, netdev@...r.kernel.org, operations@...eground.com Subject: Re: [PATCH v3] netfilter: ipset: Fix sleeping memory allocation in atomic context On Fri, 16 Oct 2015, Nikolay Borisov wrote: > 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 <kadlec@...ckhole.kfki.hu> > Signed-off-by: Nikolay Borisov <kernel@...p.com> > --- > > Changes since v2: > * Massaged the changelog to reflect discussion > on the mailing list > > Changes since v1: > * Added acked-by > * Fixed patch header > > > > net/netfilter/ipset/ip_set_list_set.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) The patch is applied in the ipset package tree. Thanks! Best regards, Jozsef - E-mail : kadlec@...ckhole.kfki.hu, kadlecsik.jozsef@...ner.mta.hu PGP key : http://www.kfki.hu/~kadlec/pgp_public_key.txt Address : Wigner Research Centre for Physics, Hungarian Academy of Sciences H-1525 Budapest 114, POB. 49, Hungary -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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