On Thu, Jul 9, 2026 at 6:23 PM Greg KH <[email protected]> wrote:
>
> On Thu, Jul 09, 2026 at 06:12:40PM +0530, Ujjal Roy wrote:
> > On Thu, Jul 9, 2026 at 4:34 PM Greg KH <[email protected]> wrote:
> > >
> > > On Thu, Jul 09, 2026 at 10:13:27AM +0000, Ujjal Roy wrote:
> > > > Hi Greg,
> > > >
> > > > Please consider backporting the following bridge multicast fix series 
> > > > to 6.1.y, 6.6.y, 6.12.y, 6.18.y and 7.0.y.
> > > >
> > > > 726fa7da2d8c ("ipv4: igmp: get rid of IGMPV3_{QQIC,MRC} and simplify 
> > > > calculation")
> > > > 12cfb4ecc471 ("ipv6: mld: rename mldv2_mrc() and add mldv2_qqi()")
> > > > 95bfd196f0dc ("ipv4: igmp: encode multicast exponential fields")
> > > > e51560f4220a ("ipv6: mld: encode multicast exponential fields")
> > > > 529dbe762de0 ("selftests: net: bridge: add MRC and QQIC field encoding 
> > > > tests")
> > >
> > > Why is any of this needed in older kernels?
> > >
> > > And 7.0.y is long end-of-life.
> > >
> > > And why, if this does fix issues, was it not tagged for stable to start
> > > with?
> > >
> > > thanks,
> > >
> > > greg k-h
> >
> > I already explained this in the email thread, "Please backport bridge
> > multicast exponential field encoding fix series to stable kernels".
>
> Sorry, but that's not here (remember, some of us get 1000+ emails a
> day.)
>
> Please explain why patches need to be backported when asking for them to
> be backported.
>
> thanks,
>
> greg k-h

Sorry for breaking the thread. I understand your point, I will
maintain this in the future.
How should I send the patchset that addresses the conflicts on 5.10.y
and 7.1.y? Shall I send the conflicts patchset as a series via a
different thread or how? I've never done this before, so I'm asking.

Here is the explanation for why the patches need to be backported:

History: The multicast stack currently supports decoding of IGMPv3 and
MLDv2 exponential timer field encodings, but lacks the corresponding
encoding logic when generating multicast query packets. As a result,
query intervals and response codes exceeding the linear encoding range
can be transmitted incorrectly. This can cause multicast queriers and
listeners to interpret different timing values, resulting in protocol
interoperability issues, membership timeouts, and premature multicast
group expiration.

Testing: The series adds the missing encoding support for both IGMPv3
and MLDv2 and includes selftests that validate the behavior.
I backported the series to v6.6.123.2 and verified the accompanying
selftests. The selftests fail on the unpatched kernel and pass after
applying the series, demonstrating both the bug and the effectiveness
of the fix.

Given that this is a protocol correctness issue affecting multicast
query generation, please consider backporting the complete series to
all applicable stable kernels.

Reply via email to