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BUG: KCSAN: data-race in do_notify_parent_cldstop / ptrace_resume

write to 0xffff888154b12508 of 4 bytes by task 2032 on cpu 0:
 ptrace_resume+0x13f/0x1c0 kernel/ptrace.c:883
 ptrace_request+0x84f/0x1210 kernel/ptrace.c:1221
 arch_ptrace+0x57/0x230 arch/x86/kernel/ptrace.c:829
 __do_sys_ptrace kernel/ptrace.c:1312 [inline]
 __se_sys_ptrace+0xf8/0x1b0 kernel/ptrace.c:1277
 __x64_sys_ptrace+0x51/0x60 kernel/ptrace.c:1277
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888154b12508 of 4 bytes by task 2035 on cpu 1:
 do_notify_parent_cldstop+0x1a3/0x280 kernel/signal.c:2083
 ptrace_stop+0x2e2/0x670 kernel/signal.c:2227
 ptrace_signal kernel/signal.c:2516 [inline]
 get_signal+0xbcc/0x15e0 kernel/signal.c:2696
 arch_do_signal_or_restart+0x2a/0x220 arch/x86/kernel/signal.c:865
 handle_signal_work kernel/entry/common.c:148 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:172 [inline]
 exit_to_user_mode_prepare+0x109/0x190 kernel/entry/common.c:209
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:302
 do_syscall_64+0x49/0x90 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00000013 -> 0x00000009

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 2035 Comm: syz-executor.0 Not tainted 5.14.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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