syzbot

==================================================================
BUG: KCSAN: data-race in dequeue_signal / ptrace_check_attach

read-write to 0xffff888142dfd640 of 8 bytes by task 3757 on cpu 1:
 dequeue_signal+0x3ca/0x420 kernel/signal.c:694
 get_signal+0x366/0x1090 kernel/signal.c:2772
 arch_do_signal_or_restart+0x95/0x4b0 arch/x86/kernel/signal.c:309
 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:285 [inline]
 syscall_exit_to_user_mode+0x26/0x140 kernel/entry/common.c:296
 do_syscall_64+0x4d/0xc0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff888142dfd640 of 8 bytes by task 3719 on cpu 0:
 ptrace_freeze_traced kernel/ptrace.c:200 [inline]
 ptrace_check_attach+0x7e/0x280 kernel/ptrace.c:267
 __do_sys_ptrace kernel/ptrace.c:1300 [inline]
 __se_sys_ptrace+0xd4/0x2a0 kernel/ptrace.c:1278
 __x64_sys_ptrace+0x55/0x60 kernel/ptrace.c:1278
 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

value changed: 0x0000000000000000 -> 0x0000000008010000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 3719 Comm: syz-executor.1 Not tainted 6.5.0-syzkaller-11075-g92901222f83d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
==================================================================