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authorDavid Ahern <dsa@cumulusnetworks.com>2015-10-14 16:44:00 -0700
committerDavid S. Miller <davem@davemloft.net>2015-10-16 00:57:55 -0700
commit51161aa98d0aa4eb20952e16d6c6dbb1d085330e (patch)
tree42d13dceaed43a1b557bc39942f3fa14ebb5eba7 /net/ipv4/fib_semantics.c
parentac00737f4e8198f8ff5007c70af4dfe4fd47ea94 (diff)
net: Fix suspicious RCU usage in fib_rebalance
This command: ip route add 192.168.1.0/24 nexthop via 10.2.1.5 dev eth1 nexthop via 10.2.2.5 dev eth2 generated this suspicious RCU usage message: [ 63.249262] [ 63.249939] =============================== [ 63.251571] [ INFO: suspicious RCU usage. ] [ 63.253250] 4.3.0-rc3+ #298 Not tainted [ 63.254724] ------------------------------- [ 63.256401] ../include/linux/inetdevice.h:205 suspicious rcu_dereference_check() usage! [ 63.259450] [ 63.259450] other info that might help us debug this: [ 63.259450] [ 63.262297] [ 63.262297] rcu_scheduler_active = 1, debug_locks = 1 [ 63.264647] 1 lock held by ip/2870: [ 63.265896] #0: (rtnl_mutex){+.+.+.}, at: [<ffffffff813ebfb7>] rtnl_lock+0x12/0x14 [ 63.268858] [ 63.268858] stack backtrace: [ 63.270409] CPU: 4 PID: 2870 Comm: ip Not tainted 4.3.0-rc3+ #298 [ 63.272478] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014 [ 63.275745] 0000000000000001 ffff8800b8c9f8b8 ffffffff8125f73c ffff88013afcf301 [ 63.278185] ffff8800bab7a380 ffff8800b8c9f8e8 ffffffff8107bf30 ffff8800bb728000 [ 63.280634] ffff880139fe9a60 0000000000000000 ffff880139fe9a00 ffff8800b8c9f908 [ 63.283177] Call Trace: [ 63.283959] [<ffffffff8125f73c>] dump_stack+0x4c/0x68 [ 63.285593] [<ffffffff8107bf30>] lockdep_rcu_suspicious+0xfa/0x103 [ 63.287500] [<ffffffff8144d752>] __in_dev_get_rcu+0x48/0x4f [ 63.289169] [<ffffffff8144d797>] fib_rebalance+0x3e/0x127 [ 63.290753] [<ffffffff8144d986>] ? rcu_read_unlock+0x3e/0x5f [ 63.292442] [<ffffffff8144ea45>] fib_create_info+0xaf9/0xdcc [ 63.294093] [<ffffffff8106c12f>] ? sched_clock_local+0x12/0x75 [ 63.295791] [<ffffffff8145236a>] fib_table_insert+0x8c/0x451 [ 63.297493] [<ffffffff8144bf9c>] ? fib_get_table+0x36/0x43 [ 63.299109] [<ffffffff8144c3ca>] inet_rtm_newroute+0x43/0x51 [ 63.300709] [<ffffffff813ef684>] rtnetlink_rcv_msg+0x182/0x195 [ 63.302334] [<ffffffff8107d04c>] ? trace_hardirqs_on+0xd/0xf [ 63.303888] [<ffffffff813ebfb7>] ? rtnl_lock+0x12/0x14 [ 63.305346] [<ffffffff813ef502>] ? __rtnl_unlock+0x12/0x12 [ 63.306878] [<ffffffff81407c4c>] netlink_rcv_skb+0x3d/0x90 [ 63.308437] [<ffffffff813ec00e>] rtnetlink_rcv+0x21/0x28 [ 63.309916] [<ffffffff81407742>] netlink_unicast+0xfa/0x17f [ 63.311447] [<ffffffff81407a5e>] netlink_sendmsg+0x297/0x2dc [ 63.313029] [<ffffffff813c6cd4>] sock_sendmsg_nosec+0x12/0x1d [ 63.314597] [<ffffffff813c835b>] ___sys_sendmsg+0x196/0x21b [ 63.316125] [<ffffffff8100bf9f>] ? native_sched_clock+0x1f/0x3c [ 63.317671] [<ffffffff8106c12f>] ? sched_clock_local+0x12/0x75 [ 63.319185] [<ffffffff8106c397>] ? sched_clock_cpu+0x9d/0xb6 [ 63.320693] [<ffffffff8107e2d7>] ? __lock_is_held+0x32/0x54 [ 63.322145] [<ffffffff81159fcb>] ? __fget_light+0x4b/0x77 [ 63.323541] [<ffffffff813c8726>] __sys_sendmsg+0x3d/0x5b [ 63.324947] [<ffffffff813c8751>] SyS_sendmsg+0xd/0x19 [ 63.326274] [<ffffffff814c8f57>] entry_SYSCALL_64_fastpath+0x12/0x6f It looks like all of the code paths to fib_rebalance are under rtnl. Fixes: 0e884c78ee19 ("ipv4: L3 hash-based multipath") Cc: Peter Nørlund <pch@ordbogen.com> Signed-off-by: David Ahern <dsa@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/fib_semantics.c')
-rw-r--r--net/ipv4/fib_semantics.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index af77298c8b4f..42778d9d71e5 100644
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -545,7 +545,7 @@ static void fib_rebalance(struct fib_info *fi)
if (nh->nh_flags & RTNH_F_DEAD)
continue;
- in_dev = __in_dev_get_rcu(nh->nh_dev);
+ in_dev = __in_dev_get_rtnl(nh->nh_dev);
if (in_dev &&
IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
@@ -559,7 +559,7 @@ static void fib_rebalance(struct fib_info *fi)
change_nexthops(fi) {
int upper_bound;
- in_dev = __in_dev_get_rcu(nexthop_nh->nh_dev);
+ in_dev = __in_dev_get_rtnl(nexthop_nh->nh_dev);
if (nexthop_nh->nh_flags & RTNH_F_DEAD) {
upper_bound = -1;