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BUG: KCSAN: data-race in do_signal_stop / prepare_signal

write to 0xffff888133e4406c of 4 bytes by task 23487 on cpu 0:
 freezer_count include/linux/freezer.h:121 [inline]
 freezable_schedule include/linux/freezer.h:173 [inline]
 do_signal_stop+0x591/0x710 kernel/signal.c:2432
 get_signal+0xa16/0x1610 kernel/signal.c:2770
 arch_do_signal_or_restart+0x2a/0x220 arch/x86/kernel/signal.c:789
 handle_signal_work kernel/entry/common.c:147 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:171 [inline]
 exit_to_user_mode_prepare+0x109/0x190 kernel/entry/common.c:208
 __syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline]
 syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:301
 do_syscall_64+0x56/0x90 arch/x86/entry/common.c:57
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888133e4406c of 4 bytes by interrupt on cpu 1:
 sig_task_ignored kernel/signal.c:93 [inline]
 sig_ignored kernel/signal.c:118 [inline]
 prepare_signal+0x952/0xeb0 kernel/signal.c:1001
 send_sigqueue+0xea/0x3e0 kernel/signal.c:1897
 posix_timer_event kernel/time/posix-timers.c:354 [inline]
 posix_timer_fn+0xe8/0x210 kernel/time/posix-timers.c:380
 __run_hrtimer+0x160/0x480 kernel/time/hrtimer.c:1537
 __hrtimer_run_queues kernel/time/hrtimer.c:1601 [inline]
 hrtimer_interrupt+0x380/0xaf0 kernel/time/hrtimer.c:1663
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1089 [inline]
 __sysvec_apic_timer_interrupt+0x6f/0x1c0 arch/x86/kernel/apic/apic.c:1106
 sysvec_apic_timer_interrupt+0x64/0x80 arch/x86/kernel/apic/apic.c:1100
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:632
 smap_restore arch/x86/include/asm/smap.h:67 [inline]
 kcsan_setup_watchpoint+0x436/0x470 kernel/kcsan/core.c:595
 format_decode+0xc8/0x8a0 lib/vsprintf.c:2486
 vsnprintf+0xcd/0xed0 lib/vsprintf.c:2704
 audit_log_vformat+0x21c/0x470 kernel/audit.c:1926
 audit_log_format+0x76/0xa0 kernel/audit.c:1960
 audit_seccomp+0xcd/0xf0 kernel/auditsc.c:2661
 seccomp_log kernel/seccomp.c:1004 [inline]
 __seccomp_filter+0xc97/0xe90 kernel/seccomp.c:1279
 __secure_computing+0xfb/0x140 kernel/seccomp.c:1309
 syscall_trace_enter+0x120/0x290 kernel/entry/common.c:67
 __syscall_enter_from_user_work kernel/entry/common.c:89 [inline]
 syscall_enter_from_user_mode+0x1c/0x20 kernel/entry/common.c:107
 do_syscall_64+0x27/0x90 arch/x86/entry/common.c:42
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 13353 Comm: syz-executor.0 Not tainted 5.12.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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