From: Petr Pavlu petr.pavlu@suse.com

stable inclusion from stable-v4.19.317 commit ebde6e8a52c68dc45b4ae354e279ba74788579e7 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/IAMPH5

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

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[ Upstream commit 14a20e5b4ad998793c5f43b0330d9e1388446cf3 ]

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: 4990509f19e8 ("[NETNS][IPV6]: Make sysctls route per namespace.") Signed-off-by: Petr Pavlu petr.pavlu@suse.com Reviewed-by: David Ahern dsahern@kernel.org Link: https://lore.kernel.org/r/20240607112828.30285-1-petr.pavlu@suse.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Liu Jian liujian56@huawei.com --- net/ipv6/route.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/ipv6/route.c b/net/ipv6/route.c index e7ff0f40867b..907a5e507819 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -5186,12 +5186,12 @@ 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; }