list_add corruption. prev->next should be next (ffffffff8a1dca60), but was ffff8881d8987470. (prev=ffff8881c40b5030). ------------[ cut here ]------------ kernel BUG at lib/list_debug.c:28! kobject: 'loop4' (0000000008521071): fill_kobj_path: path = '/devices/virtual/block/loop4' invalid opcode: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 15275 Comm: syz-executor1 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:ffff8881dac06ce0 EFLAGS: 00010286 RAX: 0000000000000075 RBX: ffffffff8a1dca60 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff816621c5 RDI: 0000000000000005 RBP: ffff8881dac06cf8 R08: ffff888184644100 R09: ffffed103b585020 R10: ffffed103b585020 R11: ffff8881dac28107 R12: ffff8881cee4e6f0 R13: ffff8881cee4e480 R14: ffffffff8a1dc820 R15: ffffffff8a1dcab0 FS: 00000000022fc940(0000) GS:ffff8881dac00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000004efc78 CR3: 00000001b8ad6000 CR4: 00000000001406f0 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:arch_local_irq_enable arch/x86/include/asm/paravirt.h:776 [inline] RIP: 0010:lookup_bh_lru fs/buffer.c:1309 [inline] RIP: 0010:__find_get_block+0x330/0xf20 fs/buffer.c:1321 Code: ff df 48 c1 ea 03 80 3c 02 00 0f 85 aa 0a 00 00 48 83 3d 02 37 8f 07 00 0f 84 f0 08 00 00 e8 47 ee 9c ff fb 66 0f 1f 44 00 00 <4d> 85 ff 0f 84 3d 02 00 00 e8 32 ee 9c ff 0f 1f 44 00 00 e8 28 ee RSP: 0018:ffff888183b97430 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13 RAX: ffff888184644100 RBX: ffff8881b66355e8 RCX: 1ffff110308c8939 RDX: 0000000000000000 RSI: ffffffff81e309c9 RDI: ffff88818464497c RBP: ffff888183b975c0 R08: ffff8881846449c8 R09: 0000000000000006 R10: 0000000000000000 R11: ffff888184644100 R12: 0000000000000010 R13: dffffc0000000000 R14: 000000000000000f R15: 0000000000000000 sb_find_get_block include/linux/buffer_head.h:338 [inline] recently_deleted fs/ext4/ialloc.c:682 [inline] find_inode_bit.isra.16+0x207/0x510 fs/ext4/ialloc.c:722 __ext4_new_inode+0x1a83/0x65a0 fs/ext4/ialloc.c:914 ext4_symlink+0x4b7/0x1130 fs/ext4/namei.c:3096 vfs_symlink+0x37a/0x5d0 fs/namei.c:4127 do_symlinkat+0x242/0x2d0 fs/namei.c:4154 __do_sys_symlink fs/namei.c:4173 [inline] __se_sys_symlink fs/namei.c:4171 [inline] __x64_sys_symlink+0x59/0x80 fs/namei.c:4171 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4573a7 Code: 0f 1f 00 b8 5c 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 bd b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 58 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 9d b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fff00bbe818 EFLAGS: 00000206 ORIG_RAX: 0000000000000058 RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00000000004573a7 RDX: 00007fff00bbe897 RSI: 00000000004bd0ae RDI: 00007fff00bbe880 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000017 R10: 0000000000000075 R11: 0000000000000206 R12: 0000000000000000 R13: 0000000000000001 R14: 00000000000000fe R15: 0000000000000001 Modules linked in: ---[ end trace d8ebfae7a7263d81 ]--- 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:ffff8881dac06ce0 EFLAGS: 00010286 RAX: 0000000000000075 RBX: ffffffff8a1dca60 RCX: 0000000000000000 kobject: 'loop2' (00000000d85cd361): kobject_uevent_env RDX: 0000000000000000 RSI: ffffffff816621c5 RDI: 0000000000000005 RBP: ffff8881dac06cf8 R08: ffff888184644100 R09: ffffed103b585020 R10: ffffed103b585020 R11: ffff8881dac28107 R12: ffff8881cee4e6f0 R13: ffff8881cee4e480 R14: ffffffff8a1dc820 R15: ffffffff8a1dcab0 kobject: 'loop2' (00000000d85cd361): fill_kobj_path: path = '/devices/virtual/block/loop2' FS: 00000000022fc940(0000) GS:ffff8881dac00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000004efc78 CR3: 00000001b8ad6000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400