------------[ cut here ]------------
!valid_signal(sig)
WARNING: kernel/signal.c:2174 at do_notify_parent+0xea8/0x10b0 kernel/signal.c:2174, CPU#1: syz.3.6745/22035
Modules linked in:
CPU: 1 UID: 0 PID: 22035 Comm: syz.3.6745 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:do_notify_parent+0xea8/0x10b0 kernel/signal.c:2174
Code: f4 ff ff e8 8a f4 3d 00 41 c1 ff 08 c7 84 24 90 00 00 00 01 00 00 00 44 89 bc 24 a0 00 00 00 e9 92 f8 ff ff e8 69 f4 3d 00 90 <0f> 0b 90 45 31 f6 e9 f5 f9 ff ff e8 58 f4 3d 00 90 0f 0b 90 e9 43
RSP: 0018:ffffc9000405fa98 EFLAGS: 00010093
RAX: 0000000000000000 RBX: ffff888064c6a500 RCX: ffffffff81caaf8b
RDX: ffff888064c6a500 RSI: ffffffff81cabd77 RDI: ffff888064c6a500
RBP: 0000000000000080 R08: 0000000000000007 R09: 0000000000000040
R10: 0000000000000080 R11: 0000000000000000 R12: 1ffff9200080bf56
R13: dffffc0000000000 R14: 0000000000000080 R15: ffff888024d62500
FS:  0000000000000000(0000) GS:ffff8880d646a000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9c3d9bbd58 CR3: 0000000058e78000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 exit_notify kernel/exit.c:758 [inline]
 do_exit+0x1b84/0x2af0 kernel/exit.c:988
 do_group_exit+0xd5/0x2a0 kernel/exit.c:1119
 get_signal+0x20ff/0x2210 kernel/signal.c:3037
 arch_do_signal_or_restart+0x91/0x7e0 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:98 [inline]
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:244 [inline]
 irqentry_exit_to_user_mode include/linux/irq-entry-common.h:315 [inline]
 irqentry_exit+0x410/0x7e0 kernel/entry/common.c:162
 asm_exc_general_protection+0x26/0x30 arch/x86/include/asm/idtentry.h:612
RIP: 0033:0x7f7f9bb9ce61
Code: Unable to access opcode bytes at 0x7f7f9bb9ce37.
RSP: 002b:0000200000000030 EFLAGS: 00010217
RAX: 0000000000000000 RBX: 00007f7f9be15fa0 RCX: 00007f7f9bb9ce59
RDX: 0000200000000040 RSI: 0000200000000030 RDI: 0000000000124080
RBP: 00007f7f9bc32d6f R08: 0000200000000180 R09: 0000200000000180
R10: 0000200000000100 R11: 0000000000000202 R12: 0000000000000000
R13: 00007f7f9be16038 R14: 00007f7f9be15fa0 R15: 00007fffe6b77bd8
 </TASK>