Re: [Patch net] ipv6: initialize route null entry in addrconf_init()
From: Andrey Konovalov <hidden>
Date: 2017-05-04 12:28:39
On Thu, May 4, 2017 at 7:07 AM, Cong Wang [off-list ref] wrote:
Andrey reported a crash on init_net.ipv6.ip6_null_entry->rt6i_idev since it is always NULL. This is clearly wrong, we have code to initialize it to loopback_dev, unfortunately the order is still not correct. loopback_dev is registered very early during boot, we lose a chance to re-initialize it in notifier. addrconf_init() is called after ip6_route_init(), which means we have no chance to correct it. Fix it by moving this initialization explicitly after ipv6_add_dev(init_net.loopback_dev) in addrconf_init(). Reported-by: Andrey Konovalov <redacted> Signed-off-by: Cong Wang <redacted>
Hi Cong, This fixes the bug triggered by my reproducer. Thanks! Tested-by: Andrey Konovalov <redacted>
quoted hunk ↗ jump to hunk
--- include/net/ip6_route.h | 1 + net/ipv6/addrconf.c | 2 ++ net/ipv6/route.c | 26 +++++++++++++++----------- 3 files changed, 18 insertions(+), 11 deletions(-)diff --git a/include/net/ip6_route.h b/include/net/ip6_route.h index 9dc2c18..f5e625f 100644 --- a/include/net/ip6_route.h +++ b/include/net/ip6_route.h@@ -84,6 +84,7 @@ struct dst_entry *ip6_route_lookup(struct net *net, struct flowi6 *fl6, struct rt6_info *ip6_pol_route(struct net *net, struct fib6_table *table, int ifindex, struct flowi6 *fl6, int flags); +void ip6_route_init_special_entries(void); int ip6_route_init(void); void ip6_route_cleanup(void);diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index a2a370b..77a4bd5 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c@@ -6573,6 +6573,8 @@ int __init addrconf_init(void) goto errlo; } + ip6_route_init_special_entries(); + for (i = 0; i < IN6_ADDR_HSIZE; i++) INIT_HLIST_HEAD(&inet6_addr_lst[i]);diff --git a/net/ipv6/route.c b/net/ipv6/route.c index a1bf426..2f11366 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c@@ -4027,6 +4027,21 @@ static struct notifier_block ip6_route_dev_notifier = { .priority = 0, }; +void __init ip6_route_init_special_entries(void) +{ + /* Registering of the loopback is done before this portion of code, + * the loopback reference in rt6_info will not be taken, do it + * manually for init_net */ + init_net.ipv6.ip6_null_entry->dst.dev = init_net.loopback_dev; + init_net.ipv6.ip6_null_entry->rt6i_idev = in6_dev_get(init_net.loopback_dev); + #ifdef CONFIG_IPV6_MULTIPLE_TABLES + init_net.ipv6.ip6_prohibit_entry->dst.dev = init_net.loopback_dev; + init_net.ipv6.ip6_prohibit_entry->rt6i_idev = in6_dev_get(init_net.loopback_dev); + init_net.ipv6.ip6_blk_hole_entry->dst.dev = init_net.loopback_dev; + init_net.ipv6.ip6_blk_hole_entry->rt6i_idev = in6_dev_get(init_net.loopback_dev); + #endif +} + int __init ip6_route_init(void) { int ret;@@ -4053,17 +4068,6 @@ int __init ip6_route_init(void) ip6_dst_blackhole_ops.kmem_cachep = ip6_dst_ops_template.kmem_cachep; - /* Registering of the loopback is done before this portion of code, - * the loopback reference in rt6_info will not be taken, do it - * manually for init_net */ - init_net.ipv6.ip6_null_entry->dst.dev = init_net.loopback_dev; - init_net.ipv6.ip6_null_entry->rt6i_idev = in6_dev_get(init_net.loopback_dev); - #ifdef CONFIG_IPV6_MULTIPLE_TABLES - init_net.ipv6.ip6_prohibit_entry->dst.dev = init_net.loopback_dev; - init_net.ipv6.ip6_prohibit_entry->rt6i_idev = in6_dev_get(init_net.loopback_dev); - init_net.ipv6.ip6_blk_hole_entry->dst.dev = init_net.loopback_dev; - init_net.ipv6.ip6_blk_hole_entry->rt6i_idev = in6_dev_get(init_net.loopback_dev); - #endif ret = fib6_init(); if (ret) goto out_register_subsys; --2.5.5