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BUG: KCSAN: data-race in do_signal_stop / prepare_signal

read-write to 0xffff88801f5b002c of 4 bytes by task 13467 on cpu 0:
 freezer_count include/linux/freezer.h:121 [inline]
 freezable_schedule include/linux/freezer.h:173 [inline]
 do_signal_stop+0x54f/0x6b0 kernel/signal.c:2396
 get_signal+0x645/0x1440 kernel/signal.c:2730
 arch_do_signal_or_restart+0x2a/0x270 arch/x86/kernel/signal.c:811
 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+0x109/0x1a0 kernel/entry/common.c:201
 irqentry_exit_to_user_mode+0x5/0x20 kernel/entry/common.c:315
 irqentry_exit+0xe/0x40 kernel/entry/common.c:403
 sysvec_apic_timer_interrupt+0x80/0x90 arch/x86/kernel/apic/apic.c:1096
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:628

read to 0xffff88801f5b002c of 4 bytes by interrupt on cpu 1:
 sig_task_ignored kernel/signal.c:94 [inline]
 sig_ignored kernel/signal.c:119 [inline]
 prepare_signal+0x872/0xd80 kernel/signal.c:962
 send_sigqueue+0xe7/0x400 kernel/signal.c:1861
 posix_timer_event kernel/time/posix-timers.c:354 [inline]
 posix_timer_fn+0xdd/0x1f0 kernel/time/posix-timers.c:380
 __run_hrtimer+0x133/0x420 kernel/time/hrtimer.c:1519
 __hrtimer_run_queues kernel/time/hrtimer.c:1583 [inline]
 hrtimer_interrupt+0x36e/0xa10 kernel/time/hrtimer.c:1645
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1085 [inline]
 __sysvec_apic_timer_interrupt+0x6f/0x200 arch/x86/kernel/apic/apic.c:1102
 asm_call_irq_on_stack+0xf/0x20
 __run_sysvec_on_irqstack arch/x86/include/asm/irq_stack.h:37 [inline]
 run_sysvec_on_irqstack_cond arch/x86/include/asm/irq_stack.h:89 [inline]
 sysvec_apic_timer_interrupt+0x52/0x90 arch/x86/kernel/apic/apic.c:1096
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:628
 native_restore_fl arch/x86/include/asm/irqflags.h:41 [inline]
 arch_local_irq_restore arch/x86/include/asm/irqflags.h:84 [inline]
 kcsan_setup_watchpoint+0x1fc/0x4e0 kernel/kcsan/core.c:591
 tomoyo_path_matches_pattern+0x29/0x120 security/tomoyo/util.c:941
 tomoyo_compare_name_union security/tomoyo/file.c:87 [inline]
 tomoyo_check_path_acl+0x9b/0xe0 security/tomoyo/file.c:260
 tomoyo_check_acl+0xcc/0x200 security/tomoyo/domain.c:175
 tomoyo_path_permission security/tomoyo/file.c:586 [inline]
 tomoyo_check_open_permission+0x17f/0x370 security/tomoyo/file.c:777
 tomoyo_file_open+0xd3/0xf0 security/tomoyo/tomoyo.c:313
 security_file_open+0x3f/0x90 security/security.c:1576
 do_dentry_open+0x22d/0x870 fs/open.c:804
 vfs_open+0x43/0x50 fs/open.c:931
 do_open fs/namei.c:3254 [inline]
 path_openat+0x1844/0x20a0 fs/namei.c:3371
 do_filp_open+0xbd/0x1d0 fs/namei.c:3398
 do_sys_openat2+0xa3/0x240 fs/open.c:1172
 do_sys_open fs/open.c:1188 [inline]
 __do_sys_open fs/open.c:1196 [inline]
 __se_sys_open fs/open.c:1192 [inline]
 __x64_sys_open+0xe2/0x110 fs/open.c:1192
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 4891 Comm: systemd-udevd Not tainted 5.11.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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