Bug 584536 – kernel 4.6.0-gentoo fixe igmp_max_memberships to 0

• Status: RESOLVED TEST-REQUEST
• Product: Gentoo Linux

[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.