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BUG: KCSAN: data-race in hrtimer_interrupt / print_cpu

write to 0xffff888237c1d794 of 4 bytes by interrupt on cpu 0:
 hrtimer_interrupt+0x89/0xaf0 kernel/time/hrtimer.c:1641
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1089 [inline]
 __sysvec_apic_timer_interrupt+0x6f/0x1c0 arch/x86/kernel/apic/apic.c:1106
 sysvec_apic_timer_interrupt+0x64/0x80 arch/x86/kernel/apic/apic.c:1100
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:647
 smap_restore arch/x86/include/asm/smap.h:67 [inline]
 kcsan_setup_watchpoint+0x436/0x470 kernel/kcsan/core.c:595
 EXT4_SB fs/ext4/ext4.h:1693 [inline]
 ext4_get_group_desc+0x45/0x1a0 fs/ext4/balloc.c:272
 recently_deleted fs/ext4/ialloc.c:682 [inline]
 find_inode_bit+0x132/0x330 fs/ext4/ialloc.c:728
 __ext4_new_inode+0xc7a/0x2f70 fs/ext4/ialloc.c:1063
 ext4_create+0x17c/0x310 fs/ext4/namei.c:2736
 lookup_open fs/namei.c:3215 [inline]
 open_last_lookups fs/namei.c:3285 [inline]
 path_openat+0xcd1/0x20b0 fs/namei.c:3491
 do_filp_open+0xd9/0x1f0 fs/namei.c:3521
 do_sys_openat2+0xa3/0x250 fs/open.c:1187
 do_sys_open fs/open.c:1203 [inline]
 __do_sys_open fs/open.c:1211 [inline]
 __se_sys_open fs/open.c:1207 [inline]
 __x64_sys_open+0xe2/0x110 fs/open.c:1207
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888237c1d794 of 4 bytes by task 10558 on cpu 1:
 print_cpu+0x37f/0x690 kernel/time/timer_list.c:135
 timer_list_show+0x114/0x180 kernel/time/timer_list.c:283
 seq_read_iter+0x60b/0x910 fs/seq_file.c:269
 proc_reg_read_iter+0xfc/0x170 fs/proc/inode.c:300
 call_read_iter include/linux/fs.h:2108 [inline]
 generic_file_splice_read+0x22a/0x310 fs/splice.c:311
 do_splice_to fs/splice.c:796 [inline]
 splice_direct_to_actor+0x2aa/0x650 fs/splice.c:870
 do_splice_direct+0xf5/0x170 fs/splice.c:979
 do_sendfile+0x773/0xda0 fs/read_write.c:1260
 __do_sys_sendfile64 fs/read_write.c:1325 [inline]
 __se_sys_sendfile64 fs/read_write.c:1311 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1311
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 10558 Comm: syz-executor.0 Not tainted 5.13.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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