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pfcp: Support per-netns netdev unregistration.

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pfcp_net_exit_rtnl() iterates pfcp devices whose sockets
are in the dying netns and queues them for destruction.

So the devices may reside in different netns.

Let's use unregister_netdevice_queue_net() to support per-netns
device unregistration.

list_del() is changed to list_del_init() to avoid queueing the
same device twice.

Even after pfcp_net_exit_rtnl() queues a cross-netns pfcp device,
pfcp_dellink() could be called concurrently for it (once RTNL is
removed).  In such a case, __rtnl_net_unlock() will perform the
unregistration.

We can see pfcp0 below is unregistered by the per-netns work
instead of cleanup_net().

  # bpftrace -e '#include <linux/netdevice.h>
  kprobe:pfcp_dev_uninit {
      $dev = (struct net_device *)arg0;
      printf("PID: %d | DEV: %s%s\n", pid, $dev->name, kstack());
  }
  kprobe:pfcp_net_exit_rtnl {
      printf("PID: %d%s\n", pid, kstack());
  }' &

  # ip netns add ns1
  # ip netns add ns2
  # ip -n ns1 link add pfcp0 link-netns ns2 type pfcp
  # ip netns del ns2

  PID: 12
          pfcp_net_exit_rtnl+5
          ops_undo_list+702
          cleanup_net+1122
          process_scheduled_works+2538
  ...
  PID: 462 | DEV: pfcp0
          pfcp_dev_uninit+5
          unregister_netdevice_many_notify+7129
          unregister_netdevice_many_net+1050
          rtnl_net_work_func+136
          process_scheduled_works+2538

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20260731224406.2444121-3-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Kuniyuki Iwashima 2026-07-31 22:43:41 +00:00 committed by Jakub Kicinski
parent f4418e64e6
commit 23aff4ed78
1 changed files with 7 additions and 5 deletions
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12
drivers/net/pfcp.c
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@ -227,12 +227,13 @@ static int pfcp_newlink(struct net_device *dev,
return err;
}
static void __pfcp_dellink(struct net_device *dev, struct list_head *head)
static void __pfcp_dellink(struct net *net, struct net_device *dev,
struct list_head *head)
{
struct pfcp_dev *pfcp = netdev_priv(dev);
list_del(&pfcp->list);
unregister_netdevice_queue(dev, head);
list_del_init(&pfcp->list);
unregister_netdevice_queue_net(net, dev, head);
}
static void pfcp_dellink(struct net_device *dev, struct list_head *head)
@ -243,7 +244,8 @@ static void pfcp_dellink(struct net_device *dev, struct list_head *head)
pn = net_generic(pfcp->net, pfcp_net_id);
mutex_lock(&pn->lock);
__pfcp_dellink(dev, head);
if (!list_empty(&pfcp->list))
__pfcp_dellink(dev_net(dev), dev, head);
mutex_unlock(&pn->lock);
}
@ -274,7 +276,7 @@ static void __net_exit pfcp_net_exit_rtnl(struct net *net,
mutex_lock(&pn->lock);
list_for_each_entry_safe(pfcp, pfcp_next, &pn->pfcp_dev_list, list)
__pfcp_dellink(pfcp->dev, dev_to_kill);
__pfcp_dellink(net, pfcp->dev, dev_to_kill);
mutex_unlock(&pn->lock);
}