bisecting fixing commit since f116b96685a046a89c25d4a6ba2da489145c8888 building syzkaller on d01bb02a96019cda0fa8c46e5c6d5eb66a273f17 testing commit f116b96685a046a89c25d4a6ba2da489145c8888 with gcc (GCC) 8.1.0 kernel signature: 1001966d1037a305845b925c1be73fc3cd7d1358c5d9e510b9be680ceeb02d10 all runs: crashed: divide error in tabledist testing current HEAD 9786cab674574239b04df638f825ee0e7d76a48c testing commit 9786cab674574239b04df638f825ee0e7d76a48c with gcc (GCC) 8.1.0 kernel signature: 085eb96d9b8e0aee46c18416ec2d5f4a5e751cbf3256176e98a1651d1c8f16aa all runs: crashed: divide error in tabledist revisions tested: 2, total time: 17m52.608917096s (build: 10m57.752401072s, test: 6m13.395725299s) the crash still happens on HEAD commit msg: Merge tag 'selinux-pr-20200416' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux crash: divide error in tabledist divide error: 0000 [#1] PREEMPT SMP KASAN CPU: 1 PID: 2717 Comm: kworker/1:3 Not tainted 5.7.0-rc1-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.20+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 f1 49 63 c5 48 29 c3 48 8d 04 1a 5b 41 5c 41 5d 5d c3 4c 89 e7 RSP: 0018:ffff8880aeb08be8 EFLAGS: 00010286 RAX: 000000001e300c57 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000080000000 RDI: ffffffff8a4878e0 RBP: ffff8880aeb08c00 R08: 0000000000000001 R09: ffff888097856e80 R10: ffff8880941df18f R11: ffffed101283be31 R12: 0000000000000000 R13: 0000000080000000 R14: ffff8880941df000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880aeb00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000075c000 CR3: 000000009fe01000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: tabledist net/sched/sch_netem.c:536 [inline] netem_enqueue+0xdae/0x2f40 net/sched/sch_netem.c:536 __dev_xmit_skb net/core/dev.c:3710 [inline] __dev_queue_xmit+0x105c/0x2960 net/core/dev.c:4021 dev_queue_xmit+0xb/0x10 net/core/dev.c:4085 br_dev_queue_push_xmit+0x14b/0x560 net/bridge/br_forward.c:52 br_nf_dev_queue_xmit+0x293/0x15d0 net/bridge/br_netfilter_hooks.c:803 NF_HOOK include/linux/netfilter.h:307 [inline] br_nf_post_routing+0xfbb/0x1690 net/bridge/br_netfilter_hooks.c:851 nf_hook_entry_hookfn include/linux/netfilter.h:135 [inline] nf_hook_slow+0xa3/0x170 net/netfilter/core.c:512 nf_hook include/linux/netfilter.h:262 [inline] NF_HOOK include/linux/netfilter.h:305 [inline] br_forward_finish+0x1b5/0x2f0 net/bridge/br_forward.c:65 br_nf_hook_thresh+0x269/0x3b0 net/bridge/br_netfilter_hooks.c:1022 br_nf_forward_finish+0x589/0x8b0 net/bridge/br_netfilter_hooks.c:564 NF_HOOK include/linux/netfilter.h:307 [inline] br_nf_forward_ip+0x986/0x1a00 net/bridge/br_netfilter_hooks.c:634 nf_hook_entry_hookfn include/linux/netfilter.h:135 [inline] nf_hook_slow+0xa3/0x170 net/netfilter/core.c:512 nf_hook include/linux/netfilter.h:262 [inline] NF_HOOK include/linux/netfilter.h:305 [inline] __br_forward+0x2ad/0x890 net/bridge/br_forward.c:109 deliver_clone+0x54/0xa0 net/bridge/br_forward.c:125 br_flood+0x243/0x2f0 net/bridge/br_forward.c:232 br_handle_frame_finish+0x957/0x1640 net/bridge/br_input.c:165 br_nf_hook_thresh+0x269/0x3b0 net/bridge/br_netfilter_hooks.c:1022 br_nf_pre_routing_finish_ipv6+0x618/0xb70 net/bridge/br_netfilter_ipv6.c:206 NF_HOOK include/linux/netfilter.h:307 [inline] br_nf_pre_routing_ipv6+0x3dd/0x6e0 net/bridge/br_netfilter_ipv6.c:236 br_nf_pre_routing+0x12a3/0x1b43 net/bridge/br_netfilter_hooks.c:505 nf_hook_entry_hookfn include/linux/netfilter.h:135 [inline] nf_hook_bridge_pre net/bridge/br_input.c:227 [inline] br_handle_frame+0x69e/0x10c0 net/bridge/br_input.c:352 __netif_receive_skb_core+0xe2f/0x2b60 net/core/dev.c:5088 __netif_receive_skb_one_core+0x99/0x170 net/core/dev.c:5185 __netif_receive_skb+0x1f/0x1b0 net/core/dev.c:5301 process_backlog+0x1ef/0x700 net/core/dev.c:6133 napi_poll net/core/dev.c:6571 [inline] net_rx_action+0x458/0xe40 net/core/dev.c:6639 __do_softirq+0x262/0xa02 kernel/softirq.c:292 do_softirq_own_stack+0x2a/0x40 arch/x86/entry/entry_64.S:1082 do_softirq.part.12+0x126/0x160 kernel/softirq.c:337 do_softirq kernel/softirq.c:329 [inline] __local_bh_enable_ip+0x21d/0x260 kernel/softirq.c:189 local_bh_enable include/linux/bottom_half.h:32 [inline] rcu_read_unlock_bh include/linux/rcupdate.h:690 [inline] ip6_finish_output2+0xcf8/0x2340 net/ipv6/ip6_output.c:118 __ip6_finish_output+0x36c/0x930 net/ipv6/ip6_output.c:143 ip6_finish_output+0x27/0x170 net/ipv6/ip6_output.c:153 NF_HOOK_COND include/linux/netfilter.h:296 [inline] ip6_output+0x1e4/0x750 net/ipv6/ip6_output.c:176 dst_output include/net/dst.h:435 [inline] NF_HOOK include/linux/netfilter.h:307 [inline] ndisc_send_skb+0xcac/0x12a0 net/ipv6/ndisc.c:506 ndisc_send_ns+0x2cb/0x7e0 net/ipv6/ndisc.c:648 addrconf_dad_work+0x9fb/0x1030 net/ipv6/addrconf.c:4131 process_one_work+0x893/0x1690 kernel/workqueue.c:2268 worker_thread+0x85/0xb60 kernel/workqueue.c:2414 kthread+0x354/0x420 kernel/kthread.c:268 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Modules linked in: ---[ end trace d64edc1ced12f0f0 ]--- RIP: 0010:tabledist.part.20+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 f1 49 63 c5 48 29 c3 48 8d 04 1a 5b 41 5c 41 5d 5d c3 4c 89 e7 RSP: 0018:ffff8880aeb08be8 EFLAGS: 00010286 RAX: 000000001e300c57 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000080000000 RDI: ffffffff8a4878e0 RBP: ffff8880aeb08c00 R08: 0000000000000001 R09: ffff888097856e80 R10: ffff8880941df18f R11: ffffed101283be31 R12: 0000000000000000 R13: 0000000080000000 R14: ffff8880941df000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880aeb00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000075c000 CR3: 000000009fe01000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400