Re: [PATCH net] net: neigh: fix multiple neigh timer scheduling

[David Miller <davem@davemloft.net>]

From: David Miller <davem@davemloft.net>
Date: Fri, 12 Jul 2019 15:40:47 -0700 (PDT)

> From: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
> Date: Fri, 12 Jul 2019 19:22:51 +0200
> 
>> Neigh timer can be scheduled multiple times from userspace adding
>> multiple neigh entries and forcing the neigh timer scheduling passing
>> NTF_USE in the netlink requests.
>> This will result in a refcount leak and in the following dump stack:
>  ...
>> Fix the issue unscheduling neigh_timer if selected entry is in 'IN_TIMER'
>> receiving a netlink request with NTF_USE flag set
>> 
>> Reported-by: Marek Majkowski <marek@cloudflare.com>
>> Fixes: 0c5c2d308906 ("neigh: Allow for user space users of the neighbour table")
>> Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
> 
> Applied and queued up for -stable, thanks.

Actually, reverted, you didn't test the build thoroughly as Infiniband
fails:

drivers/infiniband/core/addr.c: In function ‘dst_fetch_ha’:
drivers/infiniband/core/addr.c:337:3: error: too few arguments to function ‘neigh_event_send’
   neigh_event_send(n, NULL);
   ^~~~~~~~~~~~~~~~