=====================================
WARNING: bad unlock balance detected!
syzkaller #0 Not tainted
-------------------------------------
syz.3.1382/10838 is trying to release lock (&sighand->siglock) at:
[<ffffffff8182d4b3>] copy_process+0x2793/0x3c00
but there are no more locks to release!

other info that might help us debug this:
1 lock held by syz.3.1382/10838:
 #0: ffffffff8e171810 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: copy_process+0x212a/0x3c00

stack backtrace:
CPU: 0 UID: 0 PID: 10838 Comm: syz.3.1382 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250
 print_unlock_imbalance_bug+0xdc/0xf0
 lock_release+0x269/0x3e0
 _raw_spin_unlock+0x16/0x50
 copy_process+0x2793/0x3c00
 kernel_clone+0x21e/0x840
 __se_sys_clone3+0x256/0x2d0
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff7ab3c3489
Code: d7 08 00 48 8d 3d bc d7 08 00 e8 f2 28 f6 ff 66 90 b8 ea ff ff ff 48 85 ff 74 2c 48 85 d2 74 27 49 89 c8 b8 b3 01 00 00 0f 05 <48> 85 c0 7c 18 74 01 c3 31 ed 48 83 e4 f0 4c 89 c7 ff d2 48 89 c7
RSP: 002b:00007fff4e95b288 EFLAGS: 00000202 ORIG_RAX: 00000000000001b3
RAX: ffffffffffffffda RBX: 00007ff7ab345880 RCX: 00007ff7ab3c3489
RDX: 00007ff7ab345880 RSI: 0000000000000058 RDI: 00007fff4e95b2d0
RBP: 00007ff7ac13d6c0 R08: 00007ff7ac13d6c0 R09: 00007fff4e95b3b7
R10: 0000000000000008 R11: 0000000000000202 R12: ffffffffffffffa8
R13: 000000000000000b R14: 00007fff4e95b2d0 R15: 00007fff4e95b3b8
 </TASK>
