ip4_datagram_connect is called with BH processing enabled. Therefore we cannot use IP_INC_STATS_BH but must use IP_INC_STATS which disables BH handling before incrementing the counter.
The following trace is triggered without this patch: [ 9293.806634] __this_cpu_add operation in preemptible [00000000] code: ntpd/2150 [ 9293.813894] caller is __this_cpu_preempt_check+0x38/0x60 [ 9293.813896] CPU: 2 PID: 2150 Comm: ntpd Tainted: GF 3.12.0-rc4+ #178 [ 9293.813897] Hardware name: Hewlett-Packard HP Z230 SFF Workstation/1906, BIOS L51 v01.10 07/05/2013 [ 9293.813898] 0000000000000002 ffff8803f33fddc8 ffffffff816d57c4 ffff8803f33fdfd8 [ 9293.813903] ffff8803f33fddf8 ffffffff8137341c ffff8800366b0380 00000000ffffff9b [ 9293.813905] ffff8800366b0680 ffffffffffffff9b ffff8803f33fde38 ffffffff81373478 [ 9293.813916] Call Trace: [ 9293.813920] [<ffffffff816d57c4>] dump_stack+0x4e/0x82 [ 9293.813921] [<ffffffff8137341c>] check_preemption_disabled+0xec/0x110 [ 9293.813923] [<ffffffff81373478>] __this_cpu_preempt_check+0x38/0x60 [ 9293.813926] [<ffffffff8163cd5d>] ip4_datagram_connect+0x2cd/0x2f0 [ 9293.813929] [<ffffffff8164b73e>] inet_dgram_connect+0x2e/0x80 [ 9293.813934] [<ffffffff815c766b>] SYSC_connect+0xdb/0x100 [ 9293.813938] [<ffffffff81006e6f>] ? mask_8259A+0x2f/0x30 [ 9293.813940] [<ffffffff81010505>] ? syscall_trace_enter+0x155/0x270 [ 9293.813942] [<ffffffff815c7b2e>] SyS_connect+0xe/0x10 [ 9293.813944] [<ffffffff816e4d13>] tracesys+0xe1/0xe6 Cc: Eric Dumazet <[email protected]> Cc: [email protected] Cc: David Miller <[email protected]> Signed-off-by: Christoph Lameter <[email protected]> Index: linux/net/ipv4/datagram.c =================================================================== --- linux.orig/net/ipv4/datagram.c 2013-08-08 02:55:00.900983548 -0500 +++ linux/net/ipv4/datagram.c 2013-10-09 15:02:51.999123322 -0500 @@ -57,7 +57,7 @@ int ip4_datagram_connect(struct sock *sk if (IS_ERR(rt)) { err = PTR_ERR(rt); if (err == -ENETUNREACH) - IP_INC_STATS_BH(sock_net(sk), IPSTATS_MIB_OUTNOROUTES); + IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES); goto out; } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
