From mboxrd@z Thu Jan 1 00:00:00 1970 From: Cong Wang Subject: [Patch net] ipv6: fix rtnl lock assertion failure in ipv6_sock_ac_join() Date: Tue, 2 Sep 2014 11:07:19 -0700 Message-ID: <1409681239-4852-1-git-send-email-xiyou.wangcong@gmail.com> Cc: Cong Wang , "David S. Miller" , Hannes Frederic Sowa , Sabrina Dubroca To: netdev@vger.kernel.org Return-path: Received: from mail-pd0-f175.google.com ([209.85.192.175]:52545 "EHLO mail-pd0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750954AbaIBSHe (ORCPT ); Tue, 2 Sep 2014 14:07:34 -0400 Received: by mail-pd0-f175.google.com with SMTP id ft15so9221450pdb.34 for ; Tue, 02 Sep 2014 11:07:34 -0700 (PDT) Sender: netdev-owner@vger.kernel.org List-ID: Tommi reported the following RTNL lock assertion failure: [ 77.297196] RTNL: assertion failed at net/ipv6/addrconf.c (1699) [ 77.298080] CPU: 0 PID: 4842 Comm: trinity-main Not tainted 3.17.0-rc2+ #30 [ 77.299039] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 [ 77.299789] ffff88003d76a618 ffff880026133c50 ffffffff8238ba79 ffff880037c84520 [ 77.300829] ffff880026133c90 ffffffff820bd52b 0000000000000000 ffffffff82d86c40 [ 77.301869] 0000000000000000 00000000f76fd1e1 ffff8800382d8000 ffff8800382d8220 [ 77.302906] Call Trace: [ 77.303246] [] dump_stack+0x4d/0x66 [ 77.303928] [] addrconf_join_solict+0x4b/0xb0 [ 77.304731] [] ipv6_dev_ac_inc+0x2bb/0x330 [ 77.305498] [] ? ac6_seq_start+0x260/0x260 [ 77.306257] [] ipv6_sock_ac_join+0x26e/0x360 [ 77.307046] [] ? ipv6_sock_ac_join+0x99/0x360 [ 77.307798] [] do_ipv6_setsockopt.isra.5+0xa70/0xf20 This is due to we don't hold rtnl lock when calling addrconf_join_solict() in ipv6_sock_ac_join(). So hold rtnl lock instead of RCU lock here, after all it is not a hot path. BTW, mcast _might_ have similar problem, but I don't touch it since no one reports so far. Reported-by: Tommi Rantala Tested-by: Sabrina Dubroca Cc: David S. Miller Cc: Hannes Frederic Sowa Signed-off-by: Sabrina Dubroca Signed-off-by: Cong Wang --- include/linux/netdevice.h | 4 ++-- net/core/dev.c | 13 +++++++------ net/ipv6/anycast.c | 22 +++++++++++----------- 3 files changed, 20 insertions(+), 19 deletions(-) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 38377392..71838bb 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -2074,8 +2074,8 @@ void __dev_remove_pack(struct packet_type *pt); void dev_add_offload(struct packet_offload *po); void dev_remove_offload(struct packet_offload *po); -struct net_device *dev_get_by_flags_rcu(struct net *net, unsigned short flags, - unsigned short mask); +struct net_device *__dev_get_by_flags(struct net *net, unsigned short flags, + unsigned short mask); struct net_device *dev_get_by_name(struct net *net, const char *name); struct net_device *dev_get_by_name_rcu(struct net *net, const char *name); struct net_device *__dev_get_by_name(struct net *net, const char *name); diff --git a/net/core/dev.c b/net/core/dev.c index ab9a165..343847a 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -897,23 +897,24 @@ struct net_device *dev_getfirstbyhwtype(struct net *net, unsigned short type) EXPORT_SYMBOL(dev_getfirstbyhwtype); /** - * dev_get_by_flags_rcu - find any device with given flags + * __dev_get_by_flags - find any device with given flags * @net: the applicable net namespace * @if_flags: IFF_* values * @mask: bitmask of bits in if_flags to check * * Search for any interface with the given flags. Returns NULL if a device * is not found or a pointer to the device. Must be called inside - * rcu_read_lock(), and result refcount is unchanged. + * rtnl_lock(), and result refcount is unchanged. */ -struct net_device *dev_get_by_flags_rcu(struct net *net, unsigned short if_flags, - unsigned short mask) +struct net_device *__dev_get_by_flags(struct net *net, unsigned short if_flags, + unsigned short mask) { struct net_device *dev, *ret; + ASSERT_RTNL(); ret = NULL; - for_each_netdev_rcu(net, dev) { + for_each_netdev(net, dev) { if (((dev->flags ^ if_flags) & mask) == 0) { ret = dev; break; @@ -921,7 +922,7 @@ struct net_device *dev_get_by_flags_rcu(struct net *net, unsigned short if_flags } return ret; } -EXPORT_SYMBOL(dev_get_by_flags_rcu); +EXPORT_SYMBOL(__dev_get_by_flags); /** * dev_valid_name - check if name is okay for network device diff --git a/net/ipv6/anycast.c b/net/ipv6/anycast.c index 2101832..484ed23 100644 --- a/net/ipv6/anycast.c +++ b/net/ipv6/anycast.c @@ -77,7 +77,7 @@ int ipv6_sock_ac_join(struct sock *sk, int ifindex, const struct in6_addr *addr) pac->acl_next = NULL; pac->acl_addr = *addr; - rcu_read_lock(); + rtnl_lock(); if (ifindex == 0) { struct rt6_info *rt; @@ -90,11 +90,11 @@ int ipv6_sock_ac_join(struct sock *sk, int ifindex, const struct in6_addr *addr) goto error; } else { /* router, no matching interface: just pick one */ - dev = dev_get_by_flags_rcu(net, IFF_UP, - IFF_UP | IFF_LOOPBACK); + dev = __dev_get_by_flags(net, IFF_UP, + IFF_UP | IFF_LOOPBACK); } } else - dev = dev_get_by_index_rcu(net, ifindex); + dev = __dev_get_by_index(net, ifindex); if (dev == NULL) { err = -ENODEV; @@ -136,7 +136,7 @@ int ipv6_sock_ac_join(struct sock *sk, int ifindex, const struct in6_addr *addr) } error: - rcu_read_unlock(); + rtnl_unlock(); if (pac) sock_kfree_s(sk, pac, sizeof(*pac)); return err; @@ -171,11 +171,11 @@ int ipv6_sock_ac_drop(struct sock *sk, int ifindex, const struct in6_addr *addr) spin_unlock_bh(&ipv6_sk_ac_lock); - rcu_read_lock(); - dev = dev_get_by_index_rcu(net, pac->acl_ifindex); + rtnl_lock(); + dev = __dev_get_by_index(net, pac->acl_ifindex); if (dev) ipv6_dev_ac_dec(dev, &pac->acl_addr); - rcu_read_unlock(); + rtnl_unlock(); sock_kfree_s(sk, pac, sizeof(*pac)); return 0; @@ -198,7 +198,7 @@ void ipv6_sock_ac_close(struct sock *sk) spin_unlock_bh(&ipv6_sk_ac_lock); prev_index = 0; - rcu_read_lock(); + rtnl_lock(); while (pac) { struct ipv6_ac_socklist *next = pac->acl_next; @@ -211,7 +211,7 @@ void ipv6_sock_ac_close(struct sock *sk) sock_kfree_s(sk, pac, sizeof(*pac)); pac = next; } - rcu_read_unlock(); + rtnl_unlock(); } static void aca_put(struct ifacaddr6 *ac) @@ -331,7 +331,7 @@ int __ipv6_dev_ac_dec(struct inet6_dev *idev, const struct in6_addr *addr) return 0; } -/* called with rcu_read_lock() */ +/* called with rtnl_lock() */ static int ipv6_dev_ac_dec(struct net_device *dev, const struct in6_addr *addr) { struct inet6_dev *idev = __in6_dev_get(dev); -- 1.8.3.1