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BUG: KCSAN: data-race in ktime_get_real_seconds / timekeeping_advance

write to 0xffffffff86040b08 of 280 bytes by interrupt on cpu 0:
 timekeeping_advance+0x893/0xd80 include/linux/string.h:378
 update_wall_time+0x19/0x20 kernel/time/timekeeping.c:2137
 tick_do_update_jiffies64+0x1ae/0x260 kernel/time/tick-sched.c:94
 tick_sched_do_timer+0xd4/0xe0 kernel/time/tick-sched.c:138
 tick_sched_timer+0x43/0xe0 kernel/time/tick-sched.c:1292
 __run_hrtimer kernel/time/hrtimer.c:1514 [inline]
 __hrtimer_run_queues+0x288/0x600 kernel/time/hrtimer.c:1576
 hrtimer_interrupt+0x22a/0x480 kernel/time/hrtimer.c:1638
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline]
 smp_apic_timer_interrupt+0xdc/0x280 arch/x86/kernel/apic/apic.c:1135
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830
 find_watchpoint kernel/kcsan/core.c:63 [inline]
 __kcsan_check_watchpoint+0x85/0x180 kernel/kcsan/core.c:266
 __tsan_write4+0x18/0x40 kernel/kcsan/kcsan.c:35
 __rcu_read_unlock+0xc7/0x3c0 kernel/rcu/tree_plugin.h:385
 rcu_read_unlock include/linux/rcupdate.h:652 [inline]
 __unlock_page_memcg+0x42/0xa0 mm/memcontrol.c:2136
 unlock_page_memcg+0x23/0x30 mm/memcontrol.c:2145

read to 0xffffffff86040b78 of 8 bytes by task 7237 on cpu 1:
 ktime_get_real_seconds+0x20/0x40 kernel/time/timekeeping.c:127
 recently_deleted fs/ext4/ialloc.c:699 [inline]
 find_inode_bit.isra.0+0x1e2/0x300 fs/ext4/ialloc.c:722
 __ext4_new_inode+0xd4b/0x3070 fs/ext4/ialloc.c:914
 ext4_mkdir+0x289/0x820 fs/ext4/namei.c:2763
 vfs_mkdir+0x283/0x390 fs/namei.c:3807
 do_mkdirat+0x1ac/0x1f0 fs/namei.c:3830
 __do_sys_mkdirat fs/namei.c:3841 [inline]
 __se_sys_mkdirat fs/namei.c:3839 [inline]
 __x64_sys_mkdirat+0x4d/0x60 fs/namei.c:3839
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 7237 Comm: syz-fuzzer Not tainted 5.4.0-rc3+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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