BPF departure handler and interface renaming

[Ayaka Koshibe]

Hi,

I had submitted a PR for a panic caused by Open vSwitch a while back:

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=213015

It looks to be due to traffic being sent while a tap interface is
being renamed, during which if_bpf in the ifnet is set to null. The
following patch does stop the panic (it's also been added to the PR).
I see similar checks in some other departure handlers like lagg and
vxlan - so I'm wondering if this would be a sensible check here.
Thanks.


Index: net/bpf.c
===================================================================
--- net/bpf.c   (revision 313973)
+++ net/bpf.c   (working copy)
@@ -2678,6 +2678,9 @@
        struct bpf_if *bp, *bp_temp;
        int nmatched = 0;

+       if (ifp->if_flags & IFF_RENAMING)
+               return;
+
        BPF_LOCK();
        /*
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