Bug 584536

Summary:	kernel 4.6.0-gentoo fixe igmp_max_memberships to 0
Product:	Gentoo Linux	Reporter:	Cyril <cyril.baletaud>
Component:	Current packages	Assignee:	Gentoo Linux bug wranglers <bug-wranglers>
Status:	RESOLVED TEST-REQUEST
Severity:	normal	CC:	poncho
Priority:	Normal
Version:	unspecified
Hardware:	All
OS:	Linux
Whiteboard:
Package list:		Runtime testing required:	---

Description Cyril 2016-05-30 13:27:55 UTC

since kernel-4.6.0,

/proc/sys/net.ipv4/igmp_max_memberships = 0

previous kernel fixe this to 20

so service avahi-daemon can't publish IPv4 service whith error:

IP_ADD_MEMBERSHIP failed: no buffer space available 

reforcing to 20 solves the problem

Comment 1 Alex Xu (Hello71) 2016-06-05 13:41:56 UTC

torvalds/master: net/ipv4/igmp.c:2934:
        /* Sysctl initialization */
        net->ipv4.sysctl_igmp_max_memberships = 20;
        net->ipv4.sysctl_igmp_max_msf = 10;

probably your configuration somewhere is not correct.

Comment 2 Cyril 2016-06-06 05:22:20 UTC

I have 7 machines with the same problem (all).
I am the only one ?

Comment 3 Cyril 2016-06-06 05:30:55 UTC

With the same config, booting on kernel-4.5.3-gentoo fixes it to 20.
Kernel-4.6.0 was build with config.4.5.3, after make oldconfig.

Comment 4 Cyril 2016-06-06 12:08:53 UTC

I found on http://kernelnewbies.org/Linux_4.6

IGMP: Add namespaces support for the following sysctls: igmp_llm_reports commit, igmp_max_memberships commit, igmp_max_msf commit, igmp_qrv commit

someone can help with this change ?

Comment 5 poncho 2016-06-06 16:12:25 UTC

I can confirm this issue.

with sys-kernel/vanilla-sources-4.5.4 the value of /proc/sys/net/ipv4/igmp_max_memberships is 20

with sys-kernel/vanilla-sources-4.6.1 the value of /proc/sys/net/ipv4/igmp_max_memberships is 0

I didn't change any configuration.

Comment 6 Cyril 2016-06-06 19:57:25 UTC

With the change in kernel

CONFIG_IP_MULTICAST to true

igmp_max_memberships initialize to 20.

Solved for me.