bisecting fixing commit since e1f7d50ae3a3ec342e87a9b1ce6787bfb8b3c08b
building syzkaller on be5c2c81971442d623dd1b265dabf4644ceeb35b
testing commit e1f7d50ae3a3ec342e87a9b1ce6787bfb8b3c08b with gcc (GCC) 8.1.0
kernel signature: 3c612bba20002bf8223dd3721a4b4518108689af8f59617a9309ea86d12ba91b
all runs: crashed: divide error in netem_enqueue
testing current HEAD 050272a0423e68207fd2367831ae610680129062
testing commit 050272a0423e68207fd2367831ae610680129062 with gcc (GCC) 8.1.0
kernel signature: cd851ead1c433f911789ca7f7bcfefccb763ba9e9769256541f00a316825fac8
all runs: crashed: divide error in netem_enqueue
revisions tested: 2, total time: 24m42.123208648s (build: 17m29.190167073s, test: 5m59.401218942s)
the crash still happens on HEAD
commit msg: Linux 4.14.177
crash: divide error in netem_enqueue
bridge0: port 1(bridge_slave_0) entered blocking state
bridge0: port 1(bridge_slave_0) entered forwarding state
IPv6: ADDRCONF(NETDEV_CHANGE): bridge0: link becomes ready
IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready
divide error: 0000 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 1 PID: 7160 Comm: kworker/1:3 Not tainted 4.14.177-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: ipv6_addrconf addrconf_dad_work
task: ffff888090f40080 task.stack: ffff8880951b0000
RIP: 0010:packet_len_2_sched_time net/sched/sch_netem.c:352 [inline]
RIP: 0010:netem_enqueue+0x6f9/0x2a50 net/sched/sch_netem.c:562
RSP: 0018:ffff8880951b7570 EFLAGS: 00010246
RAX: 1aedcbe189692000 RBX: ffff88808ce4b47c RCX: 000000000000001e
RDX: 0000000000000000 RSI: 0000000028e31e42 RDI: ffff88808ce4b4a8
RBP: ffff8880951b7600 R08: ffff88808ce4b400 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000073a8a150
R13: 0000000073000000 R14: 000000000000205a R15: ffff88808ce4b240
FS:  0000000000000000(0000) GS:ffff8880aed00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005591f11d5000 CR3: 00000000a99ca000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __dev_xmit_skb net/core/dev.c:3229 [inline]
 __dev_queue_xmit+0x1156/0x2740 net/core/dev.c:3493
 dev_queue_xmit+0xb/0x10 net/core/dev.c:3558
 neigh_hh_output include/net/neighbour.h:490 [inline]
 neigh_output include/net/neighbour.h:498 [inline]
 ip6_finish_output2+0xf25/0x22e0 net/ipv6/ip6_output.c:120
 ip6_finish_output+0x363/0xa50 net/ipv6/ip6_output.c:154
 NF_HOOK_COND include/linux/netfilter.h:239 [inline]
 ip6_output+0x1b7/0x600 net/ipv6/ip6_output.c:171
 dst_output include/net/dst.h:462 [inline]
 NF_HOOK include/linux/netfilter.h:250 [inline]
 mld_sendpack+0x82f/0xc60 net/ipv6/mcast.c:1660
 mld_send_initial_cr.part.27+0xd7/0x110 net/ipv6/mcast.c:2077
 mld_send_initial_cr net/ipv6/mcast.c:2090 [inline]
 ipv6_mc_dad_complete+0x14d/0x1a0 net/ipv6/mcast.c:2084
 addrconf_dad_completed+0x85e/0xb90 net/ipv6/addrconf.c:4060
 addrconf_dad_work+0x61f/0xfa0 net/ipv6/addrconf.c:3991
 process_one_work+0x79e/0x16c0 kernel/workqueue.c:2116
 worker_thread+0xcc/0xee0 kernel/workqueue.c:2250
 kthread+0x338/0x400 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Code: 03 0f b6 04 02 84 c0 74 08 3c 03 0f 8e 6c 20 00 00 41 8b 87 68 02 00 00 44 01 e8 44 0f af e0 49 69 c4 00 ca 9a 3b 45 89 d2 31 d2 <49> f7 f2 48 c1 e8 06 49 01 c3 48 8b 45 d0 49 01 f3 48 8d 78 30 
RIP: packet_len_2_sched_time net/sched/sch_netem.c:352 [inline] RSP: ffff8880951b7570
RIP: netem_enqueue+0x6f9/0x2a50 net/sched/sch_netem.c:562 RSP: ffff8880951b7570
---[ end trace 12ee110121950c2d ]---