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BUG: KCSAN: data-race in internal_add_timer / update_process_times

write to 0xffff888237d176d8 of 8 bytes by interrupt on cpu 0:
 enqueue_timer kernel/time/timer.c:598 [inline]
 internal_add_timer+0x14f/0x280 kernel/time/timer.c:611
 add_timer_on+0x262/0x2a0 kernel/time/timer.c:1182
 clocksource_watchdog+0xa74/0xac0 kernel/time/clocksource.c:478
 call_timer_fn+0x2e/0x1d0 kernel/time/timer.c:1421
 expire_timers+0x135/0x240 kernel/time/timer.c:1466
 __run_timers+0x378/0x440 kernel/time/timer.c:1734
 run_timer_softirq+0x19/0x30 kernel/time/timer.c:1747
 __do_softirq+0x12c/0x26e kernel/softirq.c:558
 invoke_softirq kernel/softirq.c:432 [inline]
 __irq_exit_rcu kernel/softirq.c:636 [inline]
 irq_exit_rcu+0x4e/0xa0 kernel/softirq.c:648
 sysvec_apic_timer_interrupt+0x69/0x80 arch/x86/kernel/apic/apic.c:1097
 asm_sysvec_apic_timer_interrupt+0x12/0x20
 check_kcov_mode kernel/kcov.c:163 [inline]
 write_comp_data kernel/kcov.c:218 [inline]
 __sanitizer_cov_trace_const_cmp8+0x2b/0x90 kernel/kcov.c:291
 mark_page_accessed+0xd4/0x550 mm/swap.c:408
 touch_buffer fs/buffer.c:63 [inline]
 __find_get_block+0x72d/0x930 fs/buffer.c:1312
 sb_find_get_block include/linux/buffer_head.h:340 [inline]
 recently_deleted fs/ext4/ialloc.c:689 [inline]
 find_inode_bit+0x181/0x330 fs/ext4/ialloc.c:731
 __ext4_new_inode+0xc9a/0x2fd0 fs/ext4/ialloc.c:1066
 ext4_symlink+0x2cc/0x700 fs/ext4/namei.c:3293
 vfs_symlink+0x23f/0x350 fs/namei.c:4250
 do_symlinkat+0xf2/0x370 fs/namei.c:4279
 __do_sys_symlink fs/namei.c:4301 [inline]
 __se_sys_symlink fs/namei.c:4299 [inline]
 __x64_sys_symlink+0x52/0x60 fs/namei.c:4299
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888237d176d8 of 8 bytes by interrupt on cpu 1:
 run_local_timers kernel/time/timer.c:1761 [inline]
 update_process_times+0x8c/0x150 kernel/time/timer.c:1784
 tick_sched_handle kernel/time/tick-sched.c:226 [inline]
 tick_sched_timer+0x191/0x210 kernel/time/tick-sched.c:1421
 __run_hrtimer+0x160/0x480 kernel/time/hrtimer.c:1685
 __hrtimer_run_queues kernel/time/hrtimer.c:1749 [inline]
 hrtimer_interrupt+0x380/0xaf0 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline]
 __sysvec_apic_timer_interrupt+0x6f/0x1c0 arch/x86/kernel/apic/apic.c:1103
 sysvec_apic_timer_interrupt+0x64/0x80 arch/x86/kernel/apic/apic.c:1097
 asm_sysvec_apic_timer_interrupt+0x12/0x20
 kcsan_setup_watchpoint+0x94/0x3f0 kernel/kcsan/core.c:437
 EXT4_SB fs/ext4/ext4.h:1758 [inline]
 recently_deleted fs/ext4/ialloc.c:698 [inline]
 find_inode_bit+0x1bb/0x330 fs/ext4/ialloc.c:731
 __ext4_new_inode+0xc9a/0x2fd0 fs/ext4/ialloc.c:1066
 ext4_symlink+0x2cc/0x700 fs/ext4/namei.c:3293
 vfs_symlink+0x23f/0x350 fs/namei.c:4250
 do_symlinkat+0xf2/0x370 fs/namei.c:4279
 __do_sys_symlink fs/namei.c:4301 [inline]
 __se_sys_symlink fs/namei.c:4299 [inline]
 __x64_sys_symlink+0x52/0x60 fs/namei.c:4299
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x000000010003b200 -> 0x000000010003b1b5

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 28605 Comm: syz-executor.0 Not tainted 5.14.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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