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 Sat, 2025-11-15 at 14:02 +0100, Garri Djavadyan wrote:
> 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
The patch has landed on linux-next:
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=f72514b3c5698e4b900b25345e09f9ed33123de6
Salvatore, could you please clarify a few questions to which I could
not find clear answers in the Debian Linux kernel handbook?
- Should the patch first make it to the mainline or stable upstream
trees before it is considered for acceptance in the Debian trees?
- Will it be acceptable for both stable and oldstable Debian releases
to include the fix considering that it can be seen as a security issue
in some corner cases?
Thank you.
Regards,
Garri
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