mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-04-28 05:28:56 -04:00
60380488e4
Rafał found an issue that for non-Ethernet interface, if we down and up
frequently, the memory will be consumed slowly.
The reason is we add allnodes/allrouters addressed in multicast list in
ipv6_add_dev(). When link down, we call ipv6_mc_down(), store all multicast
addresses via mld_add_delrec(). But when link up, we don't call ipv6_mc_up()
for non-Ethernet interface to remove the addresses. This makes idev->mc_tomb
getting bigger and bigger. The call stack looks like:
addrconf_notify(NETDEV_REGISTER)
ipv6_add_dev
ipv6_dev_mc_inc(ff01::1)
ipv6_dev_mc_inc(ff02::1)
ipv6_dev_mc_inc(ff02::2)
addrconf_notify(NETDEV_UP)
addrconf_dev_config
/* Alas, we support only Ethernet autoconfiguration. */
return;
addrconf_notify(NETDEV_DOWN)
addrconf_ifdown
ipv6_mc_down
igmp6_group_dropped(ff02::2)
mld_add_delrec(ff02::2)
igmp6_group_dropped(ff02::1)
igmp6_group_dropped(ff01::1)
After investigating, I can't found a rule to disable multicast on
non-Ethernet interface. In RFC2460, the link could be Ethernet, PPP, ATM,
tunnels, etc. In IPv4, it doesn't check the dev type when calls ip_mc_up()
in inetdev_event(). Even for IPv6, we don't check the dev type and call
ipv6_add_dev(), ipv6_dev_mc_inc() after register device.
So I think it's OK to fix this memory consumer by calling ipv6_mc_up() for
non-Ethernet interface.
v2: Also check IFF_MULTICAST flag to make sure the interface supports
multicast
Reported-by: Rafał Miłecki <zajec5@gmail.com>
Tested-by: Rafał Miłecki <zajec5@gmail.com>
Fixes: 74235a25c6 ("[IPV6] addrconf: Fix IPv6 on tuntap tunnels")
Fixes: 1666d49e1d ("mld: do not remove mld souce list info when set link down")
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.