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 <[email protected]>
---
Changes since v1 [1]:
- Minimize the fix, correct only the order of operations in
ipv6_sysctl_rtcache_flush().
[1] https://lore.kernel.org/netdev/[email protected]/
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 f083d9faba6b..952c2bf11709 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -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;
}
base-commit: 8a92980606e3585d72d510a03b59906e96755b8a
--
2.35.3
On 6/7/24 5:28 AM, Petr Pavlu wrote:
> 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 <[email protected]>
> ---
>
> Changes since v1 [1]:
> - Minimize the fix, correct only the order of operations in
> ipv6_sysctl_rtcache_flush().
>
> [1] https://lore.kernel.org/netdev/[email protected]/
>
> 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 f083d9faba6b..952c2bf11709 100644
> --- a/net/ipv6/route.c
> +++ b/net/ipv6/route.c
> @@ -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;
> }
>
> base-commit: 8a92980606e3585d72d510a03b59906e96755b8a
Reviewed-by: David Ahern <[email protected]>
Hello:
This patch was applied to bpf/bpf.git (master)
by Jakub Kicinski <[email protected]>:
On Fri, 7 Jun 2024 13:28:28 +0200 you wrote:
> 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.
>
> [...]
Here is the summary with links:
- [net,v2] net/ipv6: Fix the RT cache flush via sysctl using a previous delay
https://git.kernel.org/bpf/bpf/c/14a20e5b4ad9
You are awesome, thank you!
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