syzbot

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

write to 0xffff888129f0d024 of 4 bytes by task 10784 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:2395
 get_signal+0x66a/0x1520 kernel/signal.c:2699
 do_signal+0x25/0x270 arch/x86/kernel/signal.c:810
 exit_to_usermode_loop arch/x86/entry/common.c:212 [inline]
 __prepare_exit_to_usermode+0x127/0x230 arch/x86/entry/common.c:246
 prepare_exit_to_usermode+0x5/0x20 arch/x86/entry/common.c:277
 idtentry_exit_cond_rcu+0xe/0x30 arch/x86/entry/common.c:649
 asm_sysvec_reschedule_ipi+0x12/0x20 arch/x86/include/asm/idtentry.h:601

read to 0xffff888129f0d024 of 4 bytes by interrupt on cpu 1:
 wants_signal kernel/signal.c:977 [inline]
 complete_signal+0x7c/0x600 kernel/signal.c:1000
 send_sigqueue+0x261/0x450 kernel/signal.c:1880
 posix_timer_event kernel/time/posix-timers.c:354 [inline]
 posix_timer_fn+0xe8/0x210 kernel/time/posix-timers.c:380
 __run_hrtimer+0x154/0x4b0 kernel/time/hrtimer.c:1520
 __hrtimer_run_queues kernel/time/hrtimer.c:1584 [inline]
 hrtimer_interrupt+0x37c/0xa40 kernel/time/hrtimer.c:1646
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline]
 __sysvec_apic_timer_interrupt+0xa3/0x280 arch/x86/kernel/apic/apic.c:1097
 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:711
 __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline]
 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline]
 sysvec_apic_timer_interrupt+0x80/0xd0 arch/x86/kernel/apic/apic.c:1091
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:596
 arch_local_irq_restore arch/x86/include/asm/paravirt.h:765 [inline]
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline]
 _raw_spin_unlock_irqrestore+0x44/0x70 kernel/locking/spinlock.c:191
 spin_unlock_irqrestore include/linux/spinlock.h:408 [inline]
 delete_from_page_cache_batch+0x5e4/0x830 mm/filemap.c:358
 truncate_inode_pages_range+0x492/0xf10 mm/truncate.c:366
 truncate_inode_pages mm/truncate.c:476 [inline]
 truncate_inode_pages_final+0x7d/0x90 mm/truncate.c:527
 ext4_evict_inode+0x351/0xc20 fs/ext4/inode.c:221
 evict+0x19f/0x470 fs/inode.c:576
 iput_final fs/inode.c:1652 [inline]
 iput+0x44a/0x550 fs/inode.c:1678
 do_unlinkat+0x2c9/0x4d0 fs/namei.c:3895
 __do_sys_unlink fs/namei.c:3936 [inline]
 __se_sys_unlink fs/namei.c:3934 [inline]
 __x64_sys_unlink+0x2c/0x30 fs/namei.c:3934
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 8872 Comm: syz-executor.2 Not tainted 5.8.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================