syzbot

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BUG: KCSAN: data-race in complete_signal / do_notify_parent_cldstop

write to 0xffff888104824960 of 4 bytes by task 3066 on cpu 0:
 complete_signal+0x552/0x6d0 kernel/signal.c:1053
 __send_signal_locked+0x5cc/0x700 kernel/signal.c:1189
 send_signal_locked+0x28d/0x3a0 kernel/signal.c:1252
 do_send_sig_info+0x9f/0xf0 kernel/signal.c:1295
 group_send_sig_info kernel/signal.c:1443 [inline]
 __kill_pgrp_info kernel/signal.c:1461 [inline]
 kill_something_info kernel/signal.c:1599 [inline]
 __do_sys_kill kernel/signal.c:3795 [inline]
 __se_sys_kill+0x33f/0x430 kernel/signal.c:3789
 __x64_sys_kill+0x31/0x40 kernel/signal.c:3789
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff888104824960 of 4 bytes by task 16207 on cpu 1:
 do_notify_parent_cldstop+0x192/0x290 kernel/signal.c:2188
 do_signal_stop+0x4d7/0x570 kernel/signal.c:2486
 get_signal+0x745/0xff0 kernel/signal.c:2721
 arch_do_signal_or_restart+0x89/0x2a0 arch/x86/kernel/signal.c:306
 exit_to_user_mode_loop+0x6f/0xe0 kernel/entry/common.c:168
 exit_to_user_mode_prepare+0x6c/0xb0 kernel/entry/common.c:204
 __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline]
 syscall_exit_to_user_mode+0x26/0x140 kernel/entry/common.c:297
 do_syscall_64+0x4d/0xc0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x00000014 -> 0x00000009

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 16207 Comm: syz-executor.0 Not tainted 6.3.0-syzkaller-13466-gfc4354c6e5c2 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023
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