kernel BUG at lib/list_debug.c:LINE!

[syzbot]

Hello,

syzkaller hit the following crash on
00d47fc93ae91a2d658bc573fa47e6cc4f7ca150
git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/master
compiler: gcc (GCC) 7.1.1 20170620
.config is attached
Raw console output is attached.


CC: [linux-...@vger.kernel.org linux-...@vger.kernel.org
vi...@zeniv.linux.org.uk]

RBP: 0000000000000086 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000216 R12: 00000000004b6c37
R13: 00007f3ff52b6b48 R14: 00000000004b6c47 R15: 0000000000000000
list_del corruption. prev->next should be ffff8801b58170d0, but was
ffff8801cdda6040
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:53!
invalid opcode: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
(ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 11250 Comm: syz-executor2 Not tainted 4.14.0-rc2-next-20170928+
#31
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
task: ffff8801d41482c0 task.stack: ffff8801b5810000
RIP: 0010:__list_del_entry_valid+0xef/0x150 lib/list_debug.c:51
RSP: 0018:ffff8801b5816e90 EFLAGS: 00010286
RAX: 0000000000000054 RBX: ffff8801d99e7a80 RCX: 0000000000000000
RDX: 0000000000000054 RSI: ffffffff81596f0e RDI: ffffed0036b02dc6
RBP: ffff8801b5816ea8 R08: ffff8801b5816600 R09: 0000000000000000
R10: ffff8801b5816778 R11: 0000000000000000 R12: ffff8801d99e7a80
R13: ffff8801b5817098 R14: ffff8801c63e02f0 R15: ffff8801c63e0200
FS: 00007f3ff52d8700(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000208a7f88 CR3: 00000001d3e56000 CR4: 00000000001406f0
DR0: 0000000020000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
__list_del_entry include/linux/list.h:116 [inline]
list_del include/linux/list.h:124 [inline]
__remove_wait_queue include/linux/wait.h:183 [inline]
userfaultfd_event_wait_completion+0x535/0x9c0 fs/userfaultfd.c:591
dup_fctx fs/userfaultfd.c:687 [inline]
dup_userfaultfd_complete+0x2de/0x480 fs/userfaultfd.c:695
dup_mmap kernel/fork.c:745 [inline]
dup_mm kernel/fork.c:1198 [inline]
copy_mm+0xe9b/0x1310 kernel/fork.c:1252
copy_process.part.35+0x1f0c/0x4b50 kernel/fork.c:1756
copy_process kernel/fork.c:1569 [inline]
_do_fork+0x1ef/0xfe0 kernel/fork.c:2048
SYSC_clone kernel/fork.c:2158 [inline]
SyS_clone+0x37/0x50 kernel/fork.c:2152
do_syscall_64+0x26c/0x8d0 arch/x86/entry/common.c:287
entry_SYSCALL64_slow_path+0x25/0x25
RIP: 0033:0x4520a9
RSP: 002b:00007f3ff52d7c08 EFLAGS: 00000216 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 0000000000718000 RCX: 00000000004520a9
RDX: 0000000020f1d000 RSI: 0000000020179000 RDI: 0000000000000000
RBP: 0000000000000450 R08: 0000000020ef4ffc R09: 0000000000000000
R10: 0000000020a6bffc R11: 0000000000000216 R12: 00000000004b7454
R13: 00000000ffffffff R14: 0000000000000000 R15: 0000000020179000
Code: 4c 89 e2 48 c7 c7 c0 f4 fd 84 e8 92 4d 19 ff 0f 0b 48 c7 c7 20 f5 fd
84 e8 84 4d 19 ff 0f 0b 48 c7 c7 80 f5 fd 84 e8 76 4d 19 ff <0f> 0b 48 c7
c7 e0 f5 fd 84 e8 68 4d 19 ff 0f 0b 48 89 df 48 89
RIP: __list_del_entry_valid+0xef/0x150 lib/list_debug.c:51 RSP:
ffff8801b5816e90
---[ end trace 0ce983c1e0b50e8a ]---
Kernel panic - not syncing: Fatal exception
Dumping ftrace buffer:
(ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
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[Dmitry Vyukov]

stopped happenning 2+ months ago

#syz invalid

On Tue, Oct 31, 2017 at 11:28 AM, syzbot
<bot+3d01c54b582f74c49d...@syzkaller.appspotmail.com>
wrote:

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