Commit 14a20e5b authored by Petr Pavlu's avatar Petr Pavlu Committed by Jakub Kicinski
Browse files

net/ipv6: Fix the RT cache flush via sysctl using a previous delay 



The net.ipv6.route.flush system parameter takes a value which specifies
a delay used during the flush operation for aging exception routes. The
written value is however not used in the currently requested flush and
instead utilized only in the next one.

A problem is that ipv6_sysctl_rtcache_flush() first reads the old value
of net->ipv6.sysctl.flush_delay into a local delay variable and then
calls proc_dointvec() which actually updates the sysctl based on the
provided input.

Fix the problem by switching the order of the two operations.

Fixes: 4990509f ("[NETNS][IPV6]: Make sysctls route per namespace.")
Signed-off-by: default avatarPetr Pavlu <petr.pavlu@suse.com>
Reviewed-by: default avatarDavid Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20240607112828.30285-1-petr.pavlu@suse.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent d92589f8

net/ipv6/route.c

+2 −2
Original line number Diff line number Diff line
@@ -6343,12 +6343,12 @@ static int ipv6_sysctl_rtcache_flush(struct ctl_table *ctl, int write, 
	if (!write)

		return -EINVAL;



	net = (struct net *)ctl->extra1;

	delay = net->ipv6.sysctl.flush_delay;

	ret = proc_dointvec(ctl, write, buffer, lenp, ppos);

	if (ret)

		return ret;



	net = (struct net *)ctl->extra1;

	delay = net->ipv6.sysctl.flush_delay;

	fib6_run_gc(delay <= 0 ? 0 : (unsigned long)delay, net, delay > 0);

	return 0;

}