list_add corruption. prev->next should be next (ffffffff8a1dca60), but was ffff88818541b8f0. (prev=ffff8881c38734b0). ------------[ cut here ]------------ kernel BUG at lib/list_debug.c:28! invalid opcode: 0000 [#1] PREEMPT SMP KASAN CPU: 1 PID: 28132 Comm: syz-executor4 Not tainted 4.20.0-rc6-next-20181210+ #164 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__list_add_valid.cold.2+0x23/0x2a lib/list_debug.c:26 Code: e8 00 1f d2 fd 0f 0b 48 89 d9 48 c7 c7 20 e6 80 88 e8 ef 1e d2 fd 0f 0b 48 89 f1 48 c7 c7 a0 e6 80 88 48 89 de e8 db 1e d2 fd <0f> 0b 90 90 90 90 90 55 48 89 e5 41 57 41 56 49 be 00 00 00 00 00 RSP: 0018:ffff8881dad06ce0 EFLAGS: 00010286 RAX: 0000000000000075 RBX: ffffffff8a1dca60 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff816621c5 RDI: 0000000000000005 RBP: ffff8881dad06cf8 R08: ffff8881bd4a8300 R09: ffffed103b5a5020 R10: ffffed103b5a5020 R11: ffff8881dad28107 R12: ffff88818f7114b0 R13: ffff88818f711240 R14: ffffffff8a1dc820 R15: ffffffff8a1dcab0 FS: 00007f9ba67ba700(0000) GS:ffff8881dad00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2c32f000 CR3: 00000001934bf000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __list_add include/linux/list.h:60 [inline] list_add_tail include/linux/list.h:93 [inline] neigh_alloc net/core/neighbour.c:395 [inline] ___neigh_create+0x14b7/0x2600 net/core/neighbour.c:553 __neigh_create+0x30/0x40 net/core/neighbour.c:640 ip6_finish_output2+0xa64/0x2940 net/ipv6/ip6_output.c:117 ip6_finish_output+0x58c/0xc60 net/ipv6/ip6_output.c:154 NF_HOOK_COND include/linux/netfilter.h:278 [inline] ip6_output+0x232/0x9d0 net/ipv6/ip6_output.c:171 dst_output include/net/dst.h:444 [inline] NF_HOOK include/linux/netfilter.h:289 [inline] ndisc_send_skb+0x1005/0x1560 net/ipv6/ndisc.c:491 ndisc_send_rs+0x134/0x6e0 net/ipv6/ndisc.c:685 addrconf_rs_timer+0x314/0x690 net/ipv6/addrconf.c:3840 call_timer_fn+0x272/0x920 kernel/time/timer.c:1325 expire_timers kernel/time/timer.c:1362 [inline] __run_timers+0x7e5/0xc70 kernel/time/timer.c:1681 run_timer_softirq+0x52/0xb0 kernel/time/timer.c:1694 __do_softirq+0x308/0xb7e kernel/softirq.c:292 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x17f/0x1c0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:536 [inline] smp_apic_timer_interrupt+0x1cb/0x760 arch/x86/kernel/apic/apic.c:1061 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807 RIP: 0010:write_comp_data+0x4/0x70 kernel/kcov.c:116 Code: 59 44 00 e9 a4 fc ff ff 4c 89 f7 e8 16 59 44 00 e9 6d fc ff ff e8 7c 23 c9 ff 90 90 90 90 90 90 90 90 90 90 90 90 55 48 89 e5 <65> 4c 8b 04 25 40 ee 01 00 65 8b 05 1c f6 81 7e a9 00 01 1f 00 75 RSP: 0018:ffff88818add7338 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: 0000000000000000 RBX: ffff888169c512a0 RCX: ffffffff81e386a0 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000007 RBP: ffff88818add7338 R08: ffff8881bd4a8300 R09: ffffed103b5a5b5f R10: 0000000000000004 R11: ffff8881dad2dafb R12: 0000000000001000 R13: 0000000000000e00 R14: ffff88818add75e8 R15: dffffc0000000000 __sanitizer_cov_trace_const_cmp8+0x18/0x20 kernel/kcov.c:195 __block_write_begin_int+0x4f0/0x1d90 fs/buffer.c:1992 __block_write_begin fs/buffer.c:2047 [inline] block_write_begin+0xda/0x370 fs/buffer.c:2106 cont_write_begin+0x5c4/0x920 fs/buffer.c:2459 fat_write_begin+0x8d/0x120 fs/fat/inode.c:229 generic_perform_write+0x3aa/0x6a0 mm/filemap.c:3201 __generic_file_write_iter+0x26e/0x630 mm/filemap.c:3326 generic_file_write_iter+0x34d/0x6b0 mm/filemap.c:3354 call_write_iter include/linux/fs.h:1863 [inline] new_sync_write fs/read_write.c:474 [inline] __vfs_write+0x72c/0xab0 fs/read_write.c:487 vfs_write+0x1fc/0x580 fs/read_write.c:549 ksys_write+0x101/0x260 fs/read_write.c:598 __do_sys_write fs/read_write.c:610 [inline] __se_sys_write fs/read_write.c:607 [inline] __x64_sys_write+0x73/0xb0 fs/read_write.c:607 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457679 Code: fd b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 cb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f9ba67b9c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457679 RDX: 00000000fffffd97 RSI: 0000000020000180 RDI: 0000000000000008 RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f9ba67ba6d4 R13: 00000000004c60a4 R14: 00000000004dac30 R15: 00000000ffffffff Modules linked in: ---[ end trace c5ca3e9f61a88874 ]--- RIP: 0010:__list_add_valid.cold.2+0x23/0x2a lib/list_debug.c:26 Code: e8 00 1f d2 fd 0f 0b 48 89 d9 48 c7 c7 20 e6 80 88 e8 ef 1e d2 fd 0f 0b 48 89 f1 48 c7 c7 a0 e6 80 88 48 89 de e8 db 1e d2 fd <0f> 0b 90 90 90 90 90 55 48 89 e5 41 57 41 56 49 be 00 00 00 00 00 RSP: 0018:ffff8881dad06ce0 EFLAGS: 00010286 RAX: 0000000000000075 RBX: ffffffff8a1dca60 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff816621c5 RDI: 0000000000000005 RBP: ffff8881dad06cf8 R08: ffff8881bd4a8300 R09: ffffed103b5a5020 R10: ffffed103b5a5020 R11: ffff8881dad28107 R12: ffff88818f7114b0 R13: ffff88818f711240 R14: ffffffff8a1dc820 R15: ffffffff8a1dcab0 FS: 00007f9ba67ba700(0000) GS:ffff8881dad00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2c32f000 CR3: 00000001934bf000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400