Hello,

syzkaller hit the following crash on  
11f44eb001da4c07b80055d8e24a0db4fb47eab1
git://git.cmpxchg.org/linux-mmots.git/master
compiler: gcc (GCC) 7.1.1 20170620
.config is attached
Raw console output is attached.

Unfortunately, I don't have any reproducer for this bug yet.


WARNING: CPU: 1 PID: 3084 at kernel/sched/wait.c:79  
__wake_up_common+0x433/0x770 kernel/sched/wait.c:79
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 3084 Comm: syz-fuzzer Not tainted 4.15.0-rc1-mm1+ #32
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Call Trace:
  __dump_stack lib/dump_stack.c:17 [inline]
  dump_stack+0x194/0x257 lib/dump_stack.c:53
  panic+0x1e4/0x41c kernel/panic.c:183
  __warn+0x1dc/0x200 kernel/panic.c:547
  report_bug+0x211/0x2d0 lib/bug.c:184
  fixup_bug.part.11+0x37/0x80 arch/x86/kernel/traps.c:177
  fixup_bug arch/x86/kernel/traps.c:246 [inline]
  do_error_trap+0x2d7/0x3e0 arch/x86/kernel/traps.c:295
  do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:314
  invalid_op+0x22/0x40 arch/x86/entry/entry_64.S:1066
RIP: 0010:__wake_up_common+0x433/0x770 kernel/sched/wait.c:79
RSP: 0018:ffff8801cb6874b0 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffff8801cc87e8d0 RCX: 0000000000000004
RDX: 1ffffffff0bd9741 RSI: ffff8801cc87e8e8 RDI: 0000000000000082
RBP: ffff8801cb6875b0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: ffffffff8748cda0 R12: 0000000000000000
R13: ffff8801cc87e910 R14: 0000000000000001 R15: ffff8801cc87e970
  __wake_up_locked+0x11/0x20 kernel/sched/wait.c:160
  ep_insert+0x15d0/0x1b10 fs/eventpoll.c:1495
  SYSC_epoll_ctl fs/eventpoll.c:2106 [inline]
  SyS_epoll_ctl+0x12e4/0x1ab0 fs/eventpoll.c:1992
  entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x45f7d8
RSP: 002b:000000c4203e5300 EFLAGS: 00000246 ORIG_RAX: 00000000000000e9
RAX: ffffffffffffffda RBX: 000000c42008c140 RCX: 000000000045f7d8
RDX: 0000000000000007 RSI: 0000000000000001 RDI: 0000000000000004
RBP: 000000c4203e56b8 R08: 0000000000000000 R09: 0000000000000000
R10: 000000c4203e532c R11: 0000000000000246 R12: 0000000000000000
R13: 00000000000000f2 R14: 0000000000000032 R15: 000000000000000f
Dumping ftrace buffer:
    (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
This bug is generated by a dumb bot. It may contain errors.
See https://goo.gl/tpsmEJ for details.
Direct all questions to syzkaller@googlegroups.com.
Please credit me with: Reported-by: syzbot <syzkaller@googlegroups.com>

syzbot will keep track of this bug report.
Once a fix for this bug is committed, please reply to this email with:
#syz fix: exact-commit-title
To mark this as a duplicate of another syzbot report, please reply with:
#syz dup: exact-subject-of-another-report
If it's a one-off invalid bug report, please reply with:
#syz invalid
Note: if the crash happens again, it will cause creation of a new bug  
report.
Note: all commands must start from beginning of the line in the email body.