Bug#1117959: ipv6_route flags RTF_ADDRCONF and RTF_PREFIX_RT are not cleared when static on-link routes are added during IPv6 address configuration
On Mon, 2025-11-10 at 17:54 +0100, Fernando Fernandez Mancera wrote:
>
>
> On 10/25/25 11:21 PM, Garri Djavadyan wrote:
> > On Sat, 2025-10-25 at 16:53 +0200, Salvatore Bonaccorso wrote:
> > > Hi Garri,
> > >
> > > On Sat, Oct 18, 2025 at 01:39:02AM -0700, Stephen Hemminger
> > > wrote:
> > > > On Thu, 16 Oct 2025 00:12:40 +0200
> > > > Garri Djavadyan <g.djavadyan@gmail.com> wrote:
> > > >
> > > > > Hi Everyone,
> > > > >
> > > > > A year ago I noticed a problem with handling ipv6_route flags
> > > > > that in
> > > > > some scenarios can lead to reachability issues. It was
> > > > > reported
> > > > > here:
> > > > >
> > > > > https://bugzilla.kernel.org/show_bug.cgi?id=219205
> > > > >
> > > > >
> > > > > Also it was recently reported in the Debian tracker after
> > > > > checking if
> > > > > the latest Debian stable is still affected:
> > > > >
> > > > > https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1117959
> > > > >
> > > > >
> > > > > Unfortunately, the Debian team cannot act on the report
> > > > > because
> > > > > no one
> > > > > from the upstream kernel team has confirmed if the report in
> > > > > the
> > > > > upstream tracker is valid or not. Therefore, I am checking if
> > > > > anyone
> > > > > can help confirm if the observed behavior is indeed a bug.
> > > > >
> > > > > Many thanks in advance!
> > > > >
> > > > > Regards,
> > > > > Garri
> > > > >
> > > >
> > > > Linux networking does not actively use kernel bugzilla.
> > > > I forward the reports to the mailing list, that is all.
> > > > After than sometimes developers go back and update bugzilla
> > > > but it is not required or expected.
> > >
> > > Garri, best action would likely be to really post your full
> > > report on
> > > netdev directly.
> > >
> > > Regards,
> > > Salvatore
> >
> >
> > Thank you for your suggestions Stephen and Salvatore.
> >
> > Below is the full report that was originally posted to the kernel
> > bugzilla a year ago. It is still reproducible with fresher kernels.
> >
> > -----BEGIN REPORT-----
> > I noticed that the ipv6_route flags RTF_ADDRCONF and RTF_PREFIX_RT
> > are
> > not cleared when static on-link routes are added during IPv6
> > address
> > configuration, and it leads to situations when the kernel updates
> > the
> > static on-link routes with expiration time.
> >
>
> This is indeed a bug, I have a patch already and I am doing some
> testing
> before sending it to net.git. I hope it can be sent tomorrow.
>
> Thanks,
> Fernando.
For the record, Fernando submitted the patch for review to net-next:
https://lore.kernel.org/netdev/20251115095939.6967-1-fmancera@suse.de/
Regards,
Garri
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