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 <[email protected]>
> Signed-off-by: Nikolay Borisov <[email protected]>
> ---
>
> 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 : [email protected], [email protected]
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 [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
