bisecting fixing commit since 6dd0e32665e591e9debe3edaf73c2f8135bf047e building syzkaller on 17a986e54c507287c078a70fa9eea0be9f191f84 testing commit 6dd0e32665e591e9debe3edaf73c2f8135bf047e with gcc (GCC) 8.1.0 kernel signature: 429e3b486e3dce9c4de14036f72a1e02641468c8ad9ac3a19c87fecc8e26099a all runs: crashed: divide error in tabledist testing current HEAD 3fc898571b974f9a05e4e5c1fe17b18548207091 testing commit 3fc898571b974f9a05e4e5c1fe17b18548207091 with gcc (GCC) 8.1.0 kernel signature: 906c42d4cb42bf46a3f606d1dd79b643bd0cd549daf00adbd7db523dc8b4294c all runs: crashed: divide error in tabledist revisions tested: 2, total time: 24m58.249305224s (build: 17m53.737323917s, test: 6m22.756489264s) the crash still happens on HEAD commit msg: Linux 4.19.128 crash: divide error in tabledist netlink: 32 bytes leftover after parsing attributes in process `syz-executor.2'. IPv6: ADDRCONF(NETDEV_CHANGE): batadv_slave_1: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_batadv: link becomes ready netlink: 17 bytes leftover after parsing attributes in process `syz-executor.3'. netlink: 32 bytes leftover after parsing attributes in process `syz-executor.3'. divide error: 0000 [#1] PREEMPT SMP KASAN CPU: 1 PID: 3692 Comm: systemd-udevd Not tainted 4.19.128-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:tabledist.part.18+0x10b/0x150 net/sched/sch_netem.c:333 netlink: 17 bytes leftover after parsing attributes in process `syz-executor.0'. 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:ffff8880aeb074e8 EFLAGS: 00010286 RAX: 000000001869a29c RBX: 0000003e42c00000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff87677580 RDI: ffffffff8a186960 RBP: ffff8880aeb07500 R08: 0000000000000001 R09: ffffed1015d60e93 R10: ffffed1015d60e93 R11: 0000000000000003 R12: 0000000000000000 R13: 0000000080000000 R14: ffff88808d388000 R15: 0000000000000000 FS: 00007fe1ef6068c0(0000) GS:ffff8880aeb00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fad3eaedba0 CR3: 000000008dfa9000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: netlink: 32 bytes leftover after parsing attributes in process `syz-executor.0'. tabledist net/sched/sch_netem.c:534 [inline] netem_enqueue+0x3b0/0x27a0 net/sched/sch_netem.c:534 __dev_xmit_skb net/core/dev.c:3498 [inline] __dev_queue_xmit+0x10ce/0x2a90 net/core/dev.c:3814 dev_queue_xmit+0xb/0x10 net/core/dev.c:3879 neigh_resolve_output+0x4ae/0x810 net/core/neighbour.c:1374 neigh_output include/net/neighbour.h:501 [inline] ip6_finish_output2+0x90e/0x2310 net/ipv6/ip6_output.c:120 ip6_finish_output+0x3c4/0xa90 net/ipv6/ip6_output.c:154 NF_HOOK_COND include/linux/netfilter.h:278 [inline] ip6_output+0x1bf/0x660 net/ipv6/ip6_output.c:171 dst_output include/net/dst.h:447 [inline] NF_HOOK include/linux/netfilter.h:289 [inline] ndisc_send_skb+0xcc8/0x12d0 net/ipv6/ndisc.c:491 ndisc_send_rs+0x116/0x5e0 net/ipv6/ndisc.c:685 addrconf_rs_timer+0x25c/0x5e0 net/ipv6/addrconf.c:3834 call_timer_fn+0x14c/0x510 kernel/time/timer.c:1326 expire_timers kernel/time/timer.c:1363 [inline] __run_timers kernel/time/timer.c:1684 [inline] run_timer_softirq+0xb63/0x1180 kernel/time/timer.c:1697 __do_softirq+0x260/0x92d kernel/softirq.c:292 invoke_softirq kernel/softirq.c:372 [inline] irq_exit+0x17f/0x1c0 kernel/softirq.c:412 exiting_irq arch/x86/include/asm/apic.h:544 [inline] smp_apic_timer_interrupt+0x13e/0x540 arch/x86/kernel/apic/apic.c:1094 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:894 RIP: 0010:__save_stack_trace+0x9c/0x100 arch/x86/kernel/stacktrace.c:46 Code: 2a ff ff ff 85 c0 75 27 48 8d bd 78 ff ff ff e8 aa b9 06 00 8b 85 78 ff ff ff 85 c0 74 11 48 8d bd 78 ff ff ff e8 d4 a7 06 00 <48> 85 c0 75 c7 8b 03 3b 43 04 73 11 48 8b 53 08 8d 48 01 89 0b 48 RSP: 0018:ffff88808df47308 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: ffffffff819cc74a RBX: ffff88808df473b0 RCX: 0000000000000000 RDX: 1ffff11011be8e6a RSI: 0000000000000001 RDI: ffffffff819cc74a RBP: ffff88808df47390 R08: 1ffff11011be8e6b R09: ffff88808df472b8 R10: ffff88808df47340 R11: ffff88808df47367 R12: 0000000000000000 R13: 0000000000000000 R14: ffff88808df3a0c0 R15: ffff8880a50c759f save_stack_trace+0x1a/0x20 arch/x86/kernel/stacktrace.c:60 save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553 __do_kmalloc mm/slab.c:3727 [inline] __kmalloc_track_caller+0x157/0x760 mm/slab.c:3742 kmemdup_nul+0x25/0x90 mm/util.c:138 security_context_to_sid_core.isra.15+0xa2/0x560 security/selinux/ss/services.c:1463 security_context_to_sid+0x23/0x30 security/selinux/ss/services.c:1525 selinux_inode_setsecurity+0x16d/0x430 security/selinux/hooks.c:3501 selinux_inode_notifysecctx+0x18/0x30 security/selinux/hooks.c:6667 security_inode_notifysecctx+0x4a/0x90 security/security.c:1343 kernfs_refresh_inode+0x31e/0x4a0 fs/kernfs/inode.c:195 kernfs_iop_permission+0x53/0x80 fs/kernfs/inode.c:302 do_inode_permission fs/namei.c:386 [inline] inode_permission+0x271/0x3e0 fs/namei.c:451 may_lookup fs/namei.c:1703 [inline] link_path_walk.part.40+0x6f9/0x1550 fs/namei.c:2085 link_path_walk fs/namei.c:2073 [inline] path_lookupat.isra.43+0x1aa/0x850 fs/namei.c:2318 filename_lookup.part.57+0x160/0x360 fs/namei.c:2349 filename_lookup fs/namei.c:2342 [inline] user_path_at_empty+0x39/0x40 fs/namei.c:2609 user_path_at include/linux/namei.h:57 [inline] vfs_statx+0xbe/0x150 fs/stat.c:185 vfs_lstat include/linux/fs.h:3134 [inline] __do_sys_newlstat+0x85/0xe0 fs/stat.c:350 __se_sys_newlstat fs/stat.c:344 [inline] __x64_sys_newlstat+0x4f/0x70 fs/stat.c:344 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7fe1ee479335 Code: 69 db 2b 00 64 c7 00 16 00 00 00 b8 ff ff ff ff c3 0f 1f 40 00 83 ff 01 48 89 f0 77 30 48 89 c7 48 89 d6 b8 06 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 03 f3 c3 90 48 8b 15 31 db 2b 00 f7 d8 64 89 RSP: 002b:00007fffdf889468 EFLAGS: 00000246 ORIG_RAX: 0000000000000006 RAX: ffffffffffffffda RBX: 000055d14f4b07f0 RCX: 00007fe1ee479335 RDX: 00007fffdf8894a0 RSI: 00007fffdf8894a0 RDI: 000055d14f4af7f0 RBP: 00007fffdf889560 R08: 00007fe1ee7381b8 R09: 0000000000001010 R10: 00007fe1ee737b58 R11: 0000000000000246 R12: 000055d14f4af7f0 R13: 000055d14f4af810 R14: 000055d14f49c33b R15: 000055d14f49c340 Modules linked in: ---[ end trace 4bc60f3cc816937b ]--- RIP: 0010:tabledist.part.18+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:ffff8880aeb074e8 EFLAGS: 00010286 RAX: 000000001869a29c RBX: 0000003e42c00000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff87677580 RDI: ffffffff8a186960 RBP: ffff8880aeb07500 R08: 0000000000000001 R09: ffffed1015d60e93 R10: ffffed1015d60e93 R11: 0000000000000003 R12: 0000000000000000 R13: 0000000080000000 R14: ffff88808d388000 R15: 0000000000000000 FS: 00007fe1ef6068c0(0000) GS:ffff8880aeb00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fad3eaedba0 CR3: 000000008dfa9000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400