Guys, Chris reported the bug below and confirmed that reverting commit 9704f81 (ipv6: grab rt->rt6i_ref before allocating pcpu rt) seems to have fixed the issue for him. This patch is a94b9367 in mainline. I personally have no opinion on the patch, just found it because it was the only one touching this area between 4.14.8 and 4.14.9 :-) Should this be reverted or maybe fixed differently ? thanks, Willy On Tue, Dec 26, 2017 at 01:49:59AM +0000, Chris Rankin wrote: > Hi, > > I've just raised https://bugzilla.kernel.org/show_bug.cgi?id=198271 > because the new 4.14.9 kernel is generating lots of BUG warnings, e.g. > > [ 35.069924] BUG: using smp_processor_id() in preemptible [00000000] > code: avahi-daemon/761 > [ 35.078187] caller is ip6_pol_route+0x46b/0x509 [ipv6] > [ 35.083340] CPU: 5 PID: 761 Comm: avahi-daemon Tainted: G > I 4.14.9 #1 > [ 35.091176] Hardware name: Gigabyte Technology Co., Ltd. > EX58-UD3R/EX58-UD3R, BIOS FB 05/04/2009 > [ 35.100181] Call Trace: > [ 35.102709] dump_stack+0x46/0x59 > [ 35.106095] check_preemption_disabled+0xca/0xda > [ 35.110786] ip6_pol_route+0x46b/0x509 [ipv6] > [ 35.115224] fib6_rule_lookup+0x15/0x4b [ipv6] > [ 35.119745] ip6_dst_lookup_tail+0x11d/0x18f [ipv6] > [ 35.124702] ip6_dst_lookup_flow+0x30/0x6f [ipv6] > [ 35.129481] udpv6_sendmsg+0x5c5/0xa10 [ipv6] > [ 35.133914] ? ip_reply_glue_bits+0x48/0x48 > [ 35.138187] ? rw_copy_check_uvector+0x6d/0xf9 > [ 35.142701] ? sock_sendmsg+0x28/0x34 > [ 35.146393] sock_sendmsg+0x28/0x34 > [ 35.149912] ___sys_sendmsg+0x1b4/0x246 > [ 35.153821] ? poll_select_copy_remaining+0x104/0x104 > [ 35.158995] ? current_time+0x11/0x52 > [ 35.162738] ? pipe_write+0x353/0x365 > [ 35.166483] ? __sys_sendmsg+0x3c/0x5d > [ 35.170304] __sys_sendmsg+0x3c/0x5d > [ 35.173909] do_syscall_64+0x4a/0xe1 > [ 35.177482] entry_SYSCALL64_slow_path+0x25/0x25 > [ 35.177484] RIP: 0033:0x7f963d7097b7 > [ 35.177485] RSP: 002b:00007ffff7ffbd18 EFLAGS: 00000246 ORIG_RAX: > 000000000000002e > [ 35.177486] RAX: ffffffffffffffda RBX: 000000000000000d RCX: 00007f963d7097b7 > [ 35.177487] RDX: 0000000000000000 RSI: 00007ffff7ffbde0 RDI: 000000000000000d > [ 35.177487] RBP: 0000000000000000 R08: 0000000000000001 R09: 00007ffff7ffbd42 > [ 35.177488] R10: 0000000000000002 R11: 0000000000000246 R12: 00007ffff7ffbde0 > [ 35.177489] R13: 000055e4e1af29cc R14: 000000000000000d R15: 0000000000000002 > [ 35.177565] IN=eth0 OUT= MAC= > SRC=fe80:0000:0000:0000:0224:1dff:fecd:0f3a > DST=ff02:0000:0000:0000:0000:0000:0000:00fb LEN=245 TC=0 HOPLIMIT=255 > FLOWLBL=147873 PROTO=UDP SPT=5353 DPT=5353 LEN=205 > > Cheers, > Chris