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BUG: KCSAN: data-race in run_timer_softirq / try_to_del_timer_sync

write to 0xffff88812c01dc88 of 8 bytes by interrupt on cpu 0:
 expire_timers kernel/time/timer.c:1451 [inline]
 __run_timers kernel/time/timer.c:1774 [inline]
 __run_timers kernel/time/timer.c:1741 [inline]
 run_timer_softirq+0xb1c/0xbd0 kernel/time/timer.c:1787
 __do_softirq+0x118/0x34a kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0xb5/0xd0 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:546 [inline]
 smp_apic_timer_interrupt+0xe2/0x270 arch/x86/kernel/apic/apic.c:1140
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
 __sanitizer_cov_trace_pc+0x40/0x50 kernel/kcov.c:193
 __write_once_size+0x11/0xd0 include/linux/compiler.h:246
 arch_atomic_set arch/x86/include/asm/atomic.h:43 [inline]
 atomic_set include/asm-generic/atomic-instrumented.h:46 [inline]
 inode_init_always+0x3a2/0x4b0 fs/inode.c:187
 alloc_inode+0x63/0x130 fs/inode.c:239
 new_inode_pseudo+0x32/0xe0 fs/inode.c:928
 new_inode+0x25/0x50 fs/inode.c:957
 debugfs_get_inode+0x22/0xd0 fs/debugfs/inode.c:67
 __debugfs_create_file+0xa0/0x250 fs/debugfs/inode.c:388
 debugfs_create_file+0x58/0x70 fs/debugfs/inode.c:440
 debugfs_create_files.part.0+0x6d/0x90 block/blk-mq-debugfs.c:817
 debugfs_create_files include/linux/err.h:41 [inline]
 blk_mq_debugfs_register+0xa5/0x220 block/blk-mq-debugfs.c:829
 blk_register_queue+0x171/0x360 block/blk-sysfs.c:980
 __device_add_disk+0x979/0x9e0 block/genhd.c:855
 device_add_disk+0x30/0x40 block/genhd.c:871
 add_disk include/linux/genhd.h:294 [inline]
 loop_add+0x422/0x4c0 drivers/block/loop.c:2099
 loop_control_ioctl drivers/block/loop.c:2200 [inline]
 loop_control_ioctl+0x100/0x260 drivers/block/loop.c:2182
 vfs_ioctl fs/ioctl.c:47 [inline]
 ksys_ioctl+0x101/0x150 fs/ioctl.c:763
 __do_sys_ioctl fs/ioctl.c:772 [inline]
 __se_sys_ioctl fs/ioctl.c:770 [inline]
 __x64_sys_ioctl+0x47/0x60 fs/ioctl.c:770
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88812c01dc88 of 8 bytes by task 10 on cpu 1:
 try_to_del_timer_sync+0x40/0xb0 kernel/time/timer.c:1226
 del_timer_sync+0x68/0xa0 kernel/time/timer.c:1366
 schedule_timeout+0x106/0x280 kernel/time/timer.c:1899
 rcu_gp_fqs_loop+0x34c/0x540 kernel/rcu/tree.c:1674
 rcu_gp_kthread+0x113/0x1e0 kernel/rcu/tree.c:1836
 kthread+0x203/0x230 kernel/kthread.c:268
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 10 Comm: rcu_preempt Not tainted 5.7.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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