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BUG: KCSAN: data-race in dequeue_signal / ptrace_check_attach

read-write to 0xffff88811b6b2638 of 8 bytes by task 13159 on cpu 1:
 dequeue_signal+0x308/0x3a0 kernel/signal.c:656
 get_signal+0x375/0xf60 kernel/signal.c:2914
 arch_do_signal_or_restart+0x96/0x450 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:75 [inline]
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:270 [inline]
 irqentry_exit_to_user_mode include/linux/irq-entry-common.h:339 [inline]
 irqentry_exit+0xf7/0x510 kernel/entry/common.c:196
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618

read to 0xffff88811b6b2638 of 8 bytes by task 13142 on cpu 0:
 ptrace_freeze_traced kernel/ptrace.c:189 [inline]
 ptrace_check_attach+0xa9/0x280 kernel/ptrace.c:256
 __do_sys_ptrace kernel/ptrace.c:1409 [inline]
 __se_sys_ptrace+0xd3/0x2c0 kernel/ptrace.c:1387
 __x64_sys_ptrace+0x55/0x70 kernel/ptrace.c:1387
 x64_sys_call+0x2ee5/0x3000 arch/x86/include/generated/asm/syscalls_64.h:102
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc0/0x2a0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000000000 -> 0x0000000008010000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 13142 Comm: syz.1.2865 Tainted: G        W           syzkaller #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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blktrace: Concurrent blktraces are not allowed on loop1p1