syzbot

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BUG: KCSAN: data-race in dequeue_signal / ptrace_check_attach

read-write to 0xffff88817d24c720 of 8 bytes by task 11064 on cpu 0:
 dequeue_signal+0x3de/0x430 kernel/signal.c:685
 get_signal+0x37d/0x1080 kernel/signal.c:2790
 arch_do_signal_or_restart+0x95/0x4b0 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop kernel/entry/common.c:105 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:201 [inline]
 syscall_exit_to_user_mode+0x59/0x130 kernel/entry/common.c:212
 do_syscall_64+0xe2/0x1d0 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x6d/0x75

read to 0xffff88817d24c720 of 8 bytes by task 11062 on cpu 1:
 ptrace_freeze_traced kernel/ptrace.c:189 [inline]
 ptrace_check_attach+0x7f/0x290 kernel/ptrace.c:256
 __do_sys_ptrace kernel/ptrace.c:1280 [inline]
 __se_sys_ptrace+0xd4/0x2b0 kernel/ptrace.c:1258
 __x64_sys_ptrace+0x55/0x70 kernel/ptrace.c:1258
 do_syscall_64+0xd3/0x1d0
 entry_SYSCALL_64_after_hwframe+0x6d/0x75

value changed: 0x0000000000000000 -> 0x0000000008010000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 11062 Comm: syz-executor.2 Not tainted 6.8.0-syzkaller-13182-g484193fecd2b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
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