------------[ cut here ]------------
!valid_signal(sig)
WARNING: kernel/signal.c:2174 at do_notify_parent+0xea8/0x10b0 kernel/signal.c:2174, CPU#0: syz.2.2378/15693
Modules linked in:
CPU: 0 UID: 0 PID: 15693 Comm: syz.2.2378 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 4a a7 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 29 a7 3d 00 90 <0f> 0b 90 45 31 f6 e9 f5 f9 ff ff e8 18 a7 3d 00 90 0f 0b 90 e9 43
RSP: 0018:ffffc9000403fcd0 EFLAGS: 00010093
RAX: 0000000000000000 RBX: ffff888024dba500 RCX: ffffffff81ca58ab
RDX: ffff888024dba500 RSI: ffffffff81ca6697 RDI: ffff888024dba500
RBP: 0000000000000080 R08: 0000000000000007 R09: 0000000000000040
R10: 0000000000000080 R11: 0000000000000000 R12: 1ffff92000807f9d
R13: dffffc0000000000 R14: 0000000000000080 R15: ffff888029d52500
FS:  0000000000000000(0000) GS:ffff888097171000(0000) knlGS:0000000000000000
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 00000000f7148710 CR3: 000000002a870000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 exit_notify kernel/exit.c:758 [inline]
 do_exit+0x1b84/0x2af0 kernel/exit.c:988
 __do_sys_exit kernel/exit.c:1086 [inline]
 __se_sys_exit kernel/exit.c:1084 [inline]
 __ia32_sys_exit+0x42/0x50 kernel/exit.c:1084
 ia32_sys_call+0x19ef/0x19f0 arch/x86/include/generated/asm/syscalls_32.h:2
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
 __do_fast_syscall_32+0xe7/0x950 arch/x86/entry/syscall_32.c:307
 do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:332
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf6fdef7c
Code: Unable to access opcode bytes at 0xf6fdef52.
RSP: 002b:000000008000766c EFLAGS: 00000202 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000000000000000b RCX: 000000008000774c
RDX: 000000008000774c RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>