==================================================================
BUG: KCSAN: data-race in do_signal_stop / prepare_signal

write to 0xffff888139f6c02c of 4 bytes by task 22211 on cpu 0:
 freezer_count include/linux/freezer.h:121 [inline]
 freezable_schedule include/linux/freezer.h:173 [inline]
 do_signal_stop+0x562/0x6d0 kernel/signal.c:2400
 get_signal+0x65d/0x14e0 kernel/signal.c:2737
 arch_do_signal_or_restart+0x2a/0x270 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+0x11a/0x1b0 kernel/entry/common.c:208
 irqentry_exit_to_user_mode+0x5/0x20 kernel/entry/common.c:314
 irqentry_exit+0xe/0x40 kernel/entry/common.c:405
 sysvec_apic_timer_interrupt+0x43/0x80 arch/x86/kernel/apic/apic.c:1100
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:632

read to 0xffff888139f6c02c 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+0x891/0xdb0 kernel/signal.c:966
 send_sigqueue+0xea/0x430 kernel/signal.c:1865
 posix_timer_event kernel/time/posix-timers.c:354 [inline]
 posix_timer_fn+0xe8/0x210 kernel/time/posix-timers.c:380
 __run_hrtimer+0x163/0x460 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/0x200 arch/x86/kernel/apic/apic.c:1106
 sysvec_apic_timer_interrupt+0x69/0x80 arch/x86/kernel/apic/apic.c:1100
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:632
 __tsan_unaligned_write8+0x0/0x190 kernel/kcsan/core.c:628
 pmd_page_vaddr arch/x86/include/asm/pgtable.h:829 [inline]
 pte_offset_kernel include/linux/pgtable.h:72 [inline]
 __split_huge_zero_page_pmd mm/huge_memory.c:2020 [inline]
 __split_huge_pmd_locked+0xc62/0x1100 mm/huge_memory.c:2077
 __split_huge_pmd+0x63b/0x820 mm/huge_memory.c:2260
 do_huge_pmd_wp_page+0x404/0x660 mm/huge_memory.c:1331
 wp_huge_pmd mm/memory.c:4201 [inline]
 __handle_mm_fault mm/memory.c:4443 [inline]
 handle_mm_fault+0xf88/0x1840 mm/memory.c:4551
 faultin_page mm/gup.c:850 [inline]
 __get_user_pages+0xa47/0x1000 mm/gup.c:1069
 __get_user_pages_locked mm/gup.c:1255 [inline]
 __get_user_pages_remote+0x226/0x6e0 mm/gup.c:1722
 pin_user_pages_remote+0x58/0x80 mm/gup.c:2790
 process_vm_rw_single_vec+0x17d/0x460 mm/process_vm_access.c:106
 process_vm_rw_core mm/process_vm_access.c:216 [inline]
 process_vm_rw+0x3a3/0x540 mm/process_vm_access.c:284
 __do_sys_process_vm_writev mm/process_vm_access.c:304 [inline]
 __se_sys_process_vm_writev mm/process_vm_access.c:299 [inline]
 __x64_sys_process_vm_writev+0x76/0x90 mm/process_vm_access.c:299
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 22271 Comm: syz-executor.3 Not tainted 5.12.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================