==================================================================
BUG: KCSAN: data-race in hrtimer_interrupt / print_cpu

write to 0xffff88813bd1da20 of 8 bytes by interrupt on cpu 1:
 hrtimer_interrupt+0x1fb/0xaf0 kernel/time/hrtimer.c:1655
 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
 __preempt_count_dec_and_test arch/x86/include/asm/preempt.h:95 [inline]
 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
 _raw_spin_unlock_irq+0x2c/0x40 kernel/locking/spinlock.c:199
 finish_lock_switch kernel/sched/core.c:4074 [inline]
 finish_task_switch+0xc0/0x2a0 kernel/sched/core.c:4191
 context_switch kernel/sched/core.c:4325 [inline]
 __schedule+0x3c1/0x580 kernel/sched/core.c:5073
 preempt_schedule_irq+0x43/0x80 kernel/sched/core.c:5530
 irqentry_exit_cond_resched+0x30/0x40 kernel/entry/common.c:392
 irqentry_exit+0x2a/0x40 kernel/entry/common.c:428
 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
 __preempt_count_dec_and_test arch/x86/include/asm/preempt.h:95 [inline]
 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
 _raw_spin_unlock_irq+0x2c/0x40 kernel/locking/spinlock.c:199
 spin_unlock_irq include/linux/spinlock.h:404 [inline]
 shmem_add_to_page_cache+0x605/0x6e0 mm/shmem.c:722
 shmem_getpage_gfp+0x86a/0x1980 mm/shmem.c:1929
 shmem_getpage mm/shmem.c:155 [inline]
 shmem_write_begin+0x83/0x100 mm/shmem.c:2530
 generic_perform_write+0x196/0x3a0 mm/filemap.c:3575
 __generic_file_write_iter+0x15c/0x340 mm/filemap.c:3704
 generic_file_write_iter+0x75/0x130 mm/filemap.c:3736
 call_write_iter include/linux/fs.h:1977 [inline]
 new_sync_write fs/read_write.c:518 [inline]
 vfs_write+0x6f9/0x7e0 fs/read_write.c:605
 ksys_pwrite64 fs/read_write.c:712 [inline]
 __do_sys_pwrite64 fs/read_write.c:722 [inline]
 __se_sys_pwrite64 fs/read_write.c:719 [inline]
 __x64_sys_pwrite64+0xf5/0x150 fs/read_write.c:719
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88813bd1da20 of 8 bytes by task 19447 on cpu 0:
 print_cpu+0x32e/0x690 kernel/time/timer_list.c:133
 timer_list_show+0x114/0x180 kernel/time/timer_list.c:283
 traverse+0x145/0x380 fs/seq_file.c:108
 seq_read_iter+0x859/0x910 fs/seq_file.c:192
 proc_reg_read_iter+0xfc/0x170 fs/proc/inode.c:310
 call_read_iter include/linux/fs.h:1971 [inline]
 do_iter_readv_writev+0x2e8/0x360 fs/read_write.c:738
 do_iter_read+0x109/0x4b0 fs/read_write.c:801
 vfs_readv fs/read_write.c:921 [inline]
 do_preadv+0x13b/0x230 fs/read_write.c:1013
 __do_sys_preadv fs/read_write.c:1063 [inline]
 __se_sys_preadv fs/read_write.c:1058 [inline]
 __x64_sys_preadv+0x54/0x60 fs/read_write.c:1058
 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: 0 PID: 19447 Comm: syz-executor.0 Not tainted 5.12.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================