From: Eric Dumazet <eduma...@google.com>
Date: Sat, 15 Jun 2019 16:28:48 -0700
> Nine years ago, I added RCU handling to neighbours, not pneighbours.
> (pneigh are not commonly used)
>
> Unfortunately I missed that /proc dump operations would use a
> common entry and exit point : neigh_seq_start() and neigh_seq_stop()
>
> We need to read_lock(tbl->lock) or risk use-after-free while
> iterating the pneigh structures.
>
> We might later convert pneigh to RCU and revert this patch.
>
> sysbot reported :
...
> Fixes: 767e97e1e0db ("neigh: RCU conversion of struct neighbour")
> Signed-off-by: Eric Dumazet <eduma...@google.com>
> Reported-by: syzbot <syzkal...@googlegroups.com>
Applied and queued up for -stable.
