| From 3a5ca857079ea022e0b1b17fc154f7ad7dbc150f Mon Sep 17 00:00:00 2001 |
| From: Martin Willi <martin@strongswan.org> |
| Date: Tue, 2 Mar 2021 13:24:23 +0100 |
| Subject: can: dev: Move device back to init netns on owning netns delete |
| |
| From: Martin Willi <martin@strongswan.org> |
| |
| commit 3a5ca857079ea022e0b1b17fc154f7ad7dbc150f upstream. |
| |
| When a non-initial netns is destroyed, the usual policy is to delete |
| all virtual network interfaces contained, but move physical interfaces |
| back to the initial netns. This keeps the physical interface visible |
| on the system. |
| |
| CAN devices are somewhat special, as they define rtnl_link_ops even |
| if they are physical devices. If a CAN interface is moved into a |
| non-initial netns, destroying that netns lets the interface vanish |
| instead of moving it back to the initial netns. default_device_exit() |
| skips CAN interfaces due to having rtnl_link_ops set. Reproducer: |
| |
| ip netns add foo |
| ip link set can0 netns foo |
| ip netns delete foo |
| |
| WARNING: CPU: 1 PID: 84 at net/core/dev.c:11030 ops_exit_list+0x38/0x60 |
| CPU: 1 PID: 84 Comm: kworker/u4:2 Not tainted 5.10.19 #1 |
| Workqueue: netns cleanup_net |
| [<c010e700>] (unwind_backtrace) from [<c010a1d8>] (show_stack+0x10/0x14) |
| [<c010a1d8>] (show_stack) from [<c086dc10>] (dump_stack+0x94/0xa8) |
| [<c086dc10>] (dump_stack) from [<c086b938>] (__warn+0xb8/0x114) |
| [<c086b938>] (__warn) from [<c086ba10>] (warn_slowpath_fmt+0x7c/0xac) |
| [<c086ba10>] (warn_slowpath_fmt) from [<c0629f20>] (ops_exit_list+0x38/0x60) |
| [<c0629f20>] (ops_exit_list) from [<c062a5c4>] (cleanup_net+0x230/0x380) |
| [<c062a5c4>] (cleanup_net) from [<c0142c20>] (process_one_work+0x1d8/0x438) |
| [<c0142c20>] (process_one_work) from [<c0142ee4>] (worker_thread+0x64/0x5a8) |
| [<c0142ee4>] (worker_thread) from [<c0148a98>] (kthread+0x148/0x14c) |
| [<c0148a98>] (kthread) from [<c0100148>] (ret_from_fork+0x14/0x2c) |
| |
| To properly restore physical CAN devices to the initial netns on owning |
| netns exit, introduce a flag on rtnl_link_ops that can be set by drivers. |
| For CAN devices setting this flag, default_device_exit() considers them |
| non-virtual, applying the usual namespace move. |
| |
| The issue was introduced in the commit mentioned below, as at that time |
| CAN devices did not have a dellink() operation. |
| |
| Fixes: e008b5fc8dc7 ("net: Simplfy default_device_exit and improve batching.") |
| Link: https://lore.kernel.org/r/20210302122423.872326-1-martin@strongswan.org |
| Signed-off-by: Martin Willi <martin@strongswan.org> |
| Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| drivers/net/can/dev.c | 1 + |
| include/net/rtnetlink.h | 2 ++ |
| net/core/dev.c | 2 +- |
| 3 files changed, 4 insertions(+), 1 deletion(-) |
| |
| --- a/drivers/net/can/dev.c |
| +++ b/drivers/net/can/dev.c |
| @@ -1235,6 +1235,7 @@ static void can_dellink(struct net_devic |
| |
| static struct rtnl_link_ops can_link_ops __read_mostly = { |
| .kind = "can", |
| + .netns_refund = true, |
| .maxtype = IFLA_CAN_MAX, |
| .policy = can_policy, |
| .setup = can_setup, |
| --- a/include/net/rtnetlink.h |
| +++ b/include/net/rtnetlink.h |
| @@ -33,6 +33,7 @@ static inline int rtnl_msg_family(const |
| * |
| * @list: Used internally |
| * @kind: Identifier |
| + * @netns_refund: Physical device, move to init_net on netns exit |
| * @maxtype: Highest device specific netlink attribute number |
| * @policy: Netlink policy for device specific attribute validation |
| * @validate: Optional validation function for netlink/changelink parameters |
| @@ -64,6 +65,7 @@ struct rtnl_link_ops { |
| size_t priv_size; |
| void (*setup)(struct net_device *dev); |
| |
| + bool netns_refund; |
| unsigned int maxtype; |
| const struct nla_policy *policy; |
| int (*validate)(struct nlattr *tb[], |
| --- a/net/core/dev.c |
| +++ b/net/core/dev.c |
| @@ -9708,7 +9708,7 @@ static void __net_exit default_device_ex |
| continue; |
| |
| /* Leave virtual devices for the generic cleanup */ |
| - if (dev->rtnl_link_ops) |
| + if (dev->rtnl_link_ops && !dev->rtnl_link_ops->netns_refund) |
| continue; |
| |
| /* Push remaining network devices to init_net */ |
