From: Jiri Bohac <jbo...@suse.cz>
Date: Thu, 20 Oct 2016 12:29:26 +0200
> The check for an underflow of tmp_prefered_lft is always false
> because tmp_prefered_lft is unsigned. The intention of the check
> was to guard against racing with an update of the
> temp_prefered_lft sysctl, potentially resulting in an underflow.
>
> As suggested by David Miller, the best way to prevent the race is
> by reading the sysctl variable using READ_ONCE.
>
> Signed-off-by: Jiri Bohac <jbo...@suse.cz>
> Reported-by: Julia Lawall <julia.law...@lip6.fr>
> Fixes: 76506a986dc3 ("IPv6: fix DESYNC_FACTOR")
Applied, thanks Jiri.
