bisecting fixing commit since c14d30dc9987047b439b03d6e6db7d54d9f7f180
building syzkaller on e1c29030da37d46475ab5babe68abc4afe085799
testing commit c14d30dc9987047b439b03d6e6db7d54d9f7f180 with gcc (GCC) 8.1.0
kernel signature: 27f4ae5408c1f8e2a69002e0c8758afa68af43b7a209f7a803c6f83137b00cb8
all runs: crashed: divide error in tabledist
testing current HEAD ad326970d25cc85128cd22d62398751ad072efff
testing commit ad326970d25cc85128cd22d62398751ad072efff with gcc (GCC) 8.1.0
kernel signature: fa972b26356b32a3f25eec6c409b91e64350e79da048b5723c72af8880e07e73
all runs: crashed: divide error in tabledist
revisions tested: 2, total time: 25m28.620638569s (build: 18m34.847025966s, test: 5m50.203981183s)
the crash still happens on HEAD
commit msg: Linux 4.19.152
crash: divide error in tabledist
batman_adv: batadv0: Interface activated: batadv_slave_1
IPv6: ADDRCONF(NETDEV_CHANGE): batadv_slave_1: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_batadv: link becomes ready
divide error: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 5 Comm: kworker/0:0 Not tainted 4.19.152-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: ipv6_addrconf addrconf_dad_work
RIP: 0010:tabledist.part.4+0x10b/0x150 net/sched/sch_netem.c:333
Code: 3c 18 49 8d 80 ff 1f 00 00 49 0f 49 c0 48 83 c4 08 5b 48 c1 f8 0d 41 5c 48 01 f8 41 5d 5d c3 43 8d 4c 2d 00 31 d2 48 83 c4 08 <f7> f1 49 63 c5 48 29 c3 48 8d 04 1a 5b 41 5c 41 5d 5d c3 4c 89 e7
RSP: 0018:ffff8880a9f9ebf0 EFLAGS: 00010296
RAX: 000000005a387213 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff87677ba0 RDI: ffffffff8a19da60
RBP: ffff8880a9f9ec08 R08: 0000000000000001 R09: ffffed10153f3d74
R10: ffffed10153f3d74 R11: 0000000000000003 R12: 0000000000000000
R13: 0000000080000000 R14: ffff8880a8803200 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb940873db8 CR3: 000000008a4a6000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 tabledist net/sched/sch_netem.c:534 [inline]
 netem_enqueue+0x421/0x2fb0 net/sched/sch_netem.c:534
 __dev_xmit_skb net/core/dev.c:3494 [inline]
 __dev_queue_xmit+0x1098/0x2900 net/core/dev.c:3807
 dev_queue_xmit+0xb/0x10 net/core/dev.c:3871
 neigh_hh_output include/net/neighbour.h:491 [inline]
 neigh_output include/net/neighbour.h:499 [inline]
 ip_finish_output2+0x948/0x1290 net/ipv4/ip_output.c:230
 ip_finish_output+0x402/0xb10 net/ipv4/ip_output.c:318
 NF_HOOK_COND include/linux/netfilter.h:278 [inline]
 ip_output+0x1bc/0x530 net/ipv4/ip_output.c:406
 dst_output include/net/dst.h:455 [inline]
 ip_local_out+0x74/0x110 net/ipv4/ip_output.c:125
 iptunnel_xmit+0x5ae/0x950 net/ipv4/ip_tunnel_core.c:91
 udp_tunnel_xmit_skb+0x23b/0x370 net/ipv4/udp_tunnel.c:182
 geneve_xmit_skb drivers/net/geneve.c:865 [inline]
 geneve_xmit+0xe46/0x2bb0 drivers/net/geneve.c:938
 __netdev_start_xmit include/linux/netdevice.h:4333 [inline]
 netdev_start_xmit include/linux/netdevice.h:4347 [inline]
 xmit_one net/core/dev.c:3256 [inline]
 dev_hard_start_xmit+0x160/0x6e0 net/core/dev.c:3272
 __dev_queue_xmit+0x1ca6/0x2900 net/core/dev.c:3838
 dev_queue_xmit+0xb/0x10 net/core/dev.c:3871
 neigh_resolve_output+0x4b5/0x830 net/core/neighbour.c:1374
 neigh_output include/net/neighbour.h:501 [inline]
 ip6_finish_output2+0xf4e/0x2080 net/ipv6/ip6_output.c:120
 ip6_finish_output+0x64e/0xa10 net/ipv6/ip6_output.c:154
 NF_HOOK_COND include/linux/netfilter.h:278 [inline]
 ip6_output+0x1bb/0x610 net/ipv6/ip6_output.c:171
 dst_output include/net/dst.h:455 [inline]
 NF_HOOK include/linux/netfilter.h:289 [inline]
 ndisc_send_skb+0x959/0x1340 net/ipv6/ndisc.c:491
 ndisc_send_ns+0x42a/0x7e0 net/ipv6/ndisc.c:633
 addrconf_dad_work+0x9df/0xf70 net/ipv6/addrconf.c:4075
 process_one_work+0x7b9/0x15a0 kernel/workqueue.c:2155
 worker_thread+0x85/0xb60 kernel/workqueue.c:2298
 kthread+0x347/0x410 kernel/kthread.c:259
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415
Modules linked in:
---[ end trace 91d9da20ab1af62b ]---
RIP: 0010:tabledist.part.4+0x10b/0x150 net/sched/sch_netem.c:333
divide error: 0000 [#2] PREEMPT SMP KASAN
Code: 3c 18 49 8d 80 ff 1f 00 00 49 0f 49 c0 48 83 c4 08 5b 48 c1 f8 0d 41 5c 48 01 f8 41 5d 5d c3 43 8d 4c 2d 00 31 d2 48 83 c4 08 <f7> f1 49 63 c5 48 29 c3 48 8d 04 1a 5b 41 5c 41 5d 5d c3 4c 89 e7
CPU: 1 PID: 0 Comm: swapper/1 Tainted: G      D           4.19.152-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:tabledist.part.4+0x10b/0x150 net/sched/sch_netem.c:333
Code: 3c 18 49 8d 80 ff 1f 00 00 49 0f 49 c0 48 83 c4 08 5b 48 c1 f8 0d 41 5c 48 01 f8 41 5d 5d c3 43 8d 4c 2d 00 31 d2 48 83 c4 08 <f7> f1 49 63 c5 48 29 c3 48 8d 04 1a 5b 41 5c 41 5d 5d c3 4c 89 e7
RSP: 0018:ffff8880a9f9ebf0 EFLAGS: 00010296
RSP: 0018:ffff8880aeb06d70 EFLAGS: 00010292
RAX: 000000005750f7f3 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff87677ba0 RDI: ffffffff8a19da60
RBP: ffff8880aeb06d88 R08: 0000000000000001 R09: ffffed1015d60da4
R10: ffffed1015d60da4 R11: 0000000000000003 R12: 0000000000000000
R13: 0000000080000000 R14: ffff88809f301b40 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880aeb00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
RAX: 000000005a387213 RBX: 0000000000000000 RCX: 0000000000000000
CR2: 00007fad7b4305e0 CR3: 000000009ed0a000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 tabledist net/sched/sch_netem.c:534 [inline]
 netem_enqueue+0x421/0x2fb0 net/sched/sch_netem.c:534
RDX: 0000000000000000 RSI: ffffffff87677ba0 RDI: ffffffff8a19da60
RBP: ffff8880a9f9ec08 R08: 0000000000000001 R09: ffffed10153f3d74
R10: ffffed10153f3d74 R11: 0000000000000003 R12: 0000000000000000
 __dev_xmit_skb net/core/dev.c:3494 [inline]
 __dev_queue_xmit+0x1098/0x2900 net/core/dev.c:3807
R13: 0000000080000000 R14: ffff8880a8803200 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb940873db8 CR3: 000000008a4a6000 CR4: 00000000001406f0
 dev_queue_xmit+0xb/0x10 net/core/dev.c:3871
 neigh_hh_output include/net/neighbour.h:491 [inline]
 neigh_output include/net/neighbour.h:499 [inline]
 ip_finish_output2+0x948/0x1290 net/ipv4/ip_output.c:230
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
 ip_finish_output+0x402/0xb10 net/ipv4/ip_output.c:318
 NF_HOOK_COND include/linux/netfilter.h:278 [inline]
 ip_output+0x1bc/0x530 net/ipv4/ip_output.c:406