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Groups > linux.kernel > #1710347
| From | Ido Schimmel <idosch@idosch.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: unregister_netdevice: waiting for eth0 to become free. Usage count = 1 |
| Date | 2017-08-12 20:20 +0200 |
| Message-ID | <udJaV-4mD-1@gated-at.bofh.it> (permalink) |
| References | (5 earlier) <ucOw2-1gs-13@gated-at.bofh.it> <ud0dQ-Jr-17@gated-at.bofh.it> <udlih-5Uh-3@gated-at.bofh.it> <udlV0-6mk-25@gated-at.bofh.it> <udsjM-1Rd-9@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
Hi Wei,
On Fri, Aug 11, 2017 at 05:10:02PM -0700, Wei Wang wrote:
> I think we have a potential fix for this issue.
> Martin and I found that when addrconf_dst_alloc() creates a rt6, it is
> possible that rt6->dst.dev points to loopback device while
> rt6->rt6i_idev->dev points to a real device.
> When the real device goes down, the current fib6 clean up code only
> checks for rt6->dst.dev and assumes rt6->rt6i_idev->dev is the same.
> That leaves unreleased refcnt on the real device if rt6->dst.dev
> points to loopback dev.
[...]
> From 2d8861808c2029013f6b6e86120ba6902329145b Mon Sep 17 00:00:00 2001
> From: Wei Wang <weiwan@google.com>
> Date: Fri, 11 Aug 2017 16:36:04 -0700
> Subject: [PATCH 1/2] potential fix for unregister_netdevice()
>
> Change-Id: I5d5f6f7a7ad0f5dd769f33487db17ff2570d52ea
> ---
> net/ipv6/route.c | 17 ++++++++---------
> 1 file changed, 8 insertions(+), 9 deletions(-)
>
> diff --git a/net/ipv6/route.c b/net/ipv6/route.c
> index 4d30c96a819d..105922903932 100644
> --- a/net/ipv6/route.c
> +++ b/net/ipv6/route.c
> @@ -417,14 +417,12 @@ static void ip6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
> struct net_device *loopback_dev =
> dev_net(dev)->loopback_dev;
>
> - if (dev != loopback_dev) {
> - if (idev && idev->dev == dev) {
> - struct inet6_dev *loopback_idev =
> - in6_dev_get(loopback_dev);
> - if (loopback_idev) {
> - rt->rt6i_idev = loopback_idev;
> - in6_dev_put(idev);
> - }
> + if (idev && idev->dev != loopback_dev) {
> + struct inet6_dev *loopback_idev =
> + in6_dev_get(loopback_dev);
> + if (loopback_idev) {
> + rt->rt6i_idev = loopback_idev;
> + in6_dev_put(idev);
> }
> }
> }
> @@ -2789,7 +2787,8 @@ static int fib6_ifdown(struct rt6_info *rt, void *arg)
> const struct arg_dev_net *adn = arg;
> const struct net_device *dev = adn->dev;
>
> - if ((rt->dst.dev == dev || !dev) &&
> + if ((rt->dst.dev == dev || !dev ||
> + rt->rt6i_idev->dev == dev) &&
Can you please explain why this line is needed? While host routes aren't
removed from the FIB by rt6_ifdown() (when dst.dev goes down), they are
removed later on in addrconf_ifdown().
With your patch, if I check the return value of ip6_del_rt() in
__ipv6_ifa_notify() I see that -ENONET is returned. Because the host
route was already removed by rt6_ifdown(). When the line in question is
removed from the patch I don't get the error anymore.
Is it possible that in John's case the host route was correctly removed
from the FIB and that the unreleased reference was due to a wrong check
in ip6_dst_ifdown() (which you patched correctly AFAICT)?
Thanks
> rt != adn->net->ipv6.ip6_null_entry &&
> (rt->rt6i_nsiblings == 0 ||
> (dev && netdev_unregistering(dev)) ||
> --
> 2.14.0.434.g98096fd7a8-goog
>
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unregister_netdevice: waiting for eth0 to become free. Usage count = 1 John Stultz <john.stultz@linaro.org> - 2017-08-07 23:10 +0200
Re: unregister_netdevice: waiting for eth0 to become free. Usage count = 1 John Stultz <john.stultz@linaro.org> - 2017-08-07 23:20 +0200
Re: unregister_netdevice: waiting for eth0 to become free. Usage count = 1 Cong Wang <xiyou.wangcong@gmail.com> - 2017-08-10 01:40 +0200
Re: unregister_netdevice: waiting for eth0 to become free. Usage count = 1 John Stultz <john.stultz@linaro.org> - 2017-08-10 01:50 +0200
Re: unregister_netdevice: waiting for eth0 to become free. Usage count = 1 Wei Wang <weiwan@google.com> - 2017-08-10 02:40 +0200
Re: unregister_netdevice: waiting for eth0 to become free. Usage count = 1 John Stultz <john.stultz@linaro.org> - 2017-08-10 02:50 +0200
Re: unregister_netdevice: waiting for eth0 to become free. Usage count = 1 John Stultz <john.stultz@linaro.org> - 2017-08-10 03:30 +0200
Re: unregister_netdevice: waiting for eth0 to become free. Usage count = 1 Wei Wang <weiwan@google.com> - 2017-08-10 03:40 +0200
Re: unregister_netdevice: waiting for eth0 to become free. Usage count = 1 Wei Wang <weiwan@google.com> - 2017-08-10 07:50 +0200
Re: unregister_netdevice: waiting for eth0 to become free. Usage count = 1 John Stultz <john.stultz@linaro.org> - 2017-08-10 20:20 +0200
Re: unregister_netdevice: waiting for eth0 to become free. Usage count = 1 Wei Wang <weiwan@google.com> - 2017-08-10 22:10 +0200
Re: unregister_netdevice: waiting for eth0 to become free. Usage count = 1 Cong Wang <xiyou.wangcong@gmail.com> - 2017-08-11 18:50 +0200
Re: unregister_netdevice: waiting for eth0 to become free. Usage count = 1 Wei Wang <weiwan@google.com> - 2017-08-11 19:30 +0200
Re: unregister_netdevice: waiting for eth0 to become free. Usage count = 1 David Ahern <dsahern@gmail.com> - 2017-08-12 02:20 +0200
Re: unregister_netdevice: waiting for eth0 to become free. Usage count = 1 Wei Wang <weiwan@google.com> - 2017-08-12 02:30 +0200
Re: unregister_netdevice: waiting for eth0 to become free. Usage count = 1 David Ahern <dsahern@gmail.com> - 2017-08-12 05:40 +0200
Re: unregister_netdevice: waiting for eth0 to become free. Usage count = 1 Wei Wang <weiwan@google.com> - 2017-08-12 21:40 +0200
Re: unregister_netdevice: waiting for eth0 to become free. Usage count = 1 Wei Wang <weiwan@google.com> - 2017-08-12 02:20 +0200
Re: unregister_netdevice: waiting for eth0 to become free. Usage count = 1 John Stultz <john.stultz@linaro.org> - 2017-08-12 02:40 +0200
Re: unregister_netdevice: waiting for eth0 to become free. Usage count = 1 Wei Wang <weiwan@google.com> - 2017-08-12 02:50 +0200
Re: unregister_netdevice: waiting for eth0 to become free. Usage count = 1 John Stultz <john.stultz@linaro.org> - 2017-08-12 05:10 +0200
Re: unregister_netdevice: waiting for eth0 to become free. Usage count = 1 Wei Wang <weiwan@google.com> - 2017-08-12 21:30 +0200
Re: unregister_netdevice: waiting for eth0 to become free. Usage count = 1 Wei Wang <weiwan@google.com> - 2017-08-12 21:30 +0200
Re: unregister_netdevice: waiting for eth0 to become free. Usage count = 1 Ido Schimmel <idosch@idosch.org> - 2017-08-12 20:20 +0200
Re: unregister_netdevice: waiting for eth0 to become free. Usage count = 1 Wei Wang <weiwan@google.com> - 2017-08-12 21:50 +0200
Re: unregister_netdevice: waiting for eth0 to become free. Usage count = 1 David Ahern <dsahern@gmail.com> - 2017-08-13 18:30 +0200
Re: unregister_netdevice: waiting for eth0 to become free. Usage count = 1 Wei Wang <weiwan@google.com> - 2017-08-13 23:00 +0200
Re: unregister_netdevice: waiting for eth0 to become free. Usage count = 1 David Ahern <dsahern@gmail.com> - 2017-08-14 01:10 +0200
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