syzbot

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BUG: KCSAN: data-race in get_signal / ptrace_attach

write to 0xffff8881311ba0b0 of 4 bytes by task 16150 on cpu 1:
 ptrace_attach+0x203/0x4a0 kernel/ptrace.c:422
 __do_sys_ptrace kernel/ptrace.c:1295 [inline]
 __se_sys_ptrace+0xc1/0x2d0 kernel/ptrace.c:1275
 __x64_sys_ptrace+0x51/0x60 kernel/ptrace.c:1275
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff8881311ba0b0 of 4 bytes by task 16151 on cpu 0:
 get_signal+0x63c/0x15b0 kernel/signal.c:2749
 arch_do_signal_or_restart+0x8c/0x2e0 arch/x86/kernel/signal.c:868
 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+0x113/0x190 kernel/entry/common.c:207
 irqentry_exit_to_user_mode+0x5/0x10 kernel/entry/common.c:313
 irqentry_exit+0xe/0x40 kernel/entry/common.c:404
 asm_exc_page_fault+0x1e/0x30

value changed: 0x00000000 -> 0x00010001

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 16151 Comm: syz-executor.0 Not tainted 5.17.0-rc4-syzkaller-00020-g705d84a366cf-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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