Le 23/10/2019 à 18:39, Guillaume Nault a écrit :
> In rtnl_net_notifyid(), we certainly can't pass a null GFP flag to
> rtnl_notify(). A GFP_KERNEL flag would be fine in most circumstances,
> but there are a few paths calling rtnl_net_notifyid() from atomic
> context or from RCU critical sections. The later also precludes the use
> of gfp_any() as it wouldn't detect the RCU case. Also, the nlmsg_new()
> call is wrong too, as it uses GFP_KERNEL unconditionally.
>
> Therefore, we need to pass the GFP flags as parameter and propagate it
> through function calls until the proper flags can be determined.
>
> In most cases, GFP_KERNEL is fine. The exceptions are:
> * openvswitch: ovs_vport_cmd_get() and ovs_vport_cmd_dump()
> indirectly call rtnl_net_notifyid() from RCU critical section,
>
> * rtnetlink: rtmsg_ifinfo_build_skb() already receives GFP flags as
> parameter.
>
> Also, in ovs_vport_cmd_build_info(), let's change the GFP flags used
> by nlmsg_new(). The function is allowed to sleep, so better make the
> flags consistent with the ones used in the following
> ovs_vport_cmd_fill_info() call.
>
> Found by code inspection.
>
> Fixes: 9a9634545c70 ("netns: notify netns id events")
> Signed-off-by: Guillaume Nault <gna...@redhat.com>
Acked-by: Nicolas Dichtel <nicolas.dich...@6wind.com>
