Bug#1106321: iproute2: "ip monitor" fails with current trixie's linux kernel / iproute2 combination

From	Yuyang Huang <yuyanghuang@google.com>
Newsgroups	linux.debian.bugs.dist, linux.debian.kernel
Subject	Bug#1106321: iproute2: "ip monitor" fails with current trixie's linux kernel / iproute2 combination
Date	2025-05-23 03:20 +0200
Message-ID	<KPpeN-52X7-1@gated-at.bofh.it> (permalink)
References	(3 earlier) <KPo93-52jJ-1@gated-at.bofh.it> <KPp58-52TG-3@gated-at.bofh.it> <KPpeN-52X7-3@gated-at.bofh.it> <KPk5r-4Zw3-1@gated-at.bofh.it> <KPpeN-52X7-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Cross-posted to 2 groups.

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>iproute2 is generally backward compatible with previous kernels yes,

Acked, will submit a patch ASAP.
Could you advise which branch needs the fix?
Is submitting to iproute2-next and iproute2 enough?

Thanks,

Yuyang

On Fri, May 23, 2025 at 10:10 AM Luca Boccassi <bluca@debian.org> wrote:
>
> On Fri, 23 May 2025 at 01:58, Yuyang Huang <yuyanghuang@google.com> wrote:
> >
> > Backward compatibility is broken due to the exit(1) in the following changes.
> >
> > ```
> > + if (lmask & IPMON_LMADDR) {
> > + if ((!preferred_family || preferred_family == AF_INET) &&
> > +     rtnl_add_nl_group(&rth, RTNLGRP_IPV4_MCADDR) < 0) {
> > + fprintf(stderr,
> > + "Failed to add ipv4 mcaddr group to list\n");
> > + exit(1);
> > + }
> > + if ((!preferred_family || preferred_family == AF_INET6) &&
> > +     rtnl_add_nl_group(&rth, RTNLGRP_IPV6_MCADDR) < 0) {
> > + fprintf(stderr,
> > + "Failed to add ipv6 mcaddr group to list\n");
> > + exit(1);
> > + }
> > + }
> > +
> > + if (lmask & IPMON_LACADDR) {
> > + if ((!preferred_family || preferred_family == AF_INET6) &&
> > +     rtnl_add_nl_group(&rth, RTNLGRP_IPV6_ACADDR) < 0) {
> > + fprintf(stderr,
> > + "Failed to add ipv6 acaddr group to list\n");
> > + exit(1);
> > + }
> > + }
> > +
> > ```
> >
> > My patches follow the existing code styles, so I also added exit(1).
> >
> > Link: https://git.kernel.org/pub/scm/network/iproute2/iproute2-next.git/tree/ip/ipmonitor.c#n330
> >
> > I thought iproute2 was intentionally not backward compatible, but it
> > sounds like that's not true.
> >
> > I can submit a fix patch to remove the exit(1), which should fix the
> > backward compatibility issue.
> >
> > Shall we proceed with this proposal?
>
> iproute2 is generally backward compatible with previous kernels yes,
> so it would be great to have a fix for this. Thanks!

Thread

Bug#1106321: iproute2: "ip monitor" fails with current trixie's linux kernel / iproute2 combination Adel Belhouane <bugs.a.b@free.fr> - 2025-05-22 21:50 +0200
  Bug#1106321: iproute2: "ip monitor" fails with current trixie's linux kernel / iproute2 combination Luca Boccassi <bluca@debian.org> - 2025-05-23 01:00 +0200
    Bug#1106321: iproute2: "ip monitor" fails with current trixie's linux kernel / iproute2 combination David Ahern <dsahern@kernel.org> - 2025-05-23 02:20 +0200
  Bug#1106321: iproute2: "ip monitor" fails with current trixie's linux kernel / iproute2 combination Luca Boccassi <bluca@debian.org> - 2025-05-23 02:10 +0200
    Bug#1106321: iproute2: "ip monitor" fails with current trixie's linux kernel / iproute2 combination Yuyang Huang <yuyanghuang@google.com> - 2025-05-23 03:10 +0200
  Bug#1106321: iproute2: "ip monitor" fails with current trixie's linux kernel / iproute2 combination Yuyang Huang <yuyanghuang@google.com> - 2025-05-23 03:20 +0200
    Bug#1106321: iproute2: "ip monitor" fails with current trixie's linux kernel / iproute2 combination David Ahern <dsahern@kernel.org> - 2025-05-23 04:30 +0200
  Bug#1106321: marked as done (iproute2: "ip monitor" fails with  current trixie's linux kernel / iproute2 combination) "Debian Bug Tracking System" <owner@bugs.debian.org> - 2025-05-27 02:10 +0200

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