syzbot

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BUG: KCSAN: data-race in clockevents_program_event / print_tickdevice

write to 0xffff888237d1bf18 of 8 bytes by interrupt on cpu 1:
 clockevents_program_event+0x34/0x1d0 kernel/time/clockevents.c:313
 tick_program_event+0x7c/0xc0 kernel/time/tick-oneshot.c:44
 hrtimer_interrupt+0x251/0x7b0 kernel/time/hrtimer.c:1827
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1065 [inline]
 __sysvec_apic_timer_interrupt+0x52/0x190 arch/x86/kernel/apic/apic.c:1082
 sysvec_apic_timer_interrupt+0x68/0x80 arch/x86/kernel/apic/apic.c:1076
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:649
 is_atomic kernel/kcsan/core.c:249 [inline]
 should_watch kernel/kcsan/core.c:277 [inline]
 check_access kernel/kcsan/core.c:752 [inline]
 __tsan_read8+0xe4/0x180 kernel/kcsan/core.c:1025
 native_save_fl arch/x86/include/asm/irqflags.h:32 [inline]
 arch_local_save_flags arch/x86/include/asm/irqflags.h:67 [inline]
 arch_local_irq_save arch/x86/include/asm/irqflags.h:103 [inline]
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:108 [inline]
 _raw_spin_lock_irqsave+0x3c/0xa0 kernel/locking/spinlock.c:162
 __percpu_counter_sum+0x22/0x130 lib/percpu_counter.c:143
 percpu_counter_sum_positive include/linux/percpu_counter.h:99 [inline]
 ext4_has_free_clusters+0x179/0x330 fs/ext4/balloc.c:641
 ext4_claim_free_clusters+0x24/0x80 fs/ext4/balloc.c:671
 ext4_mb_new_blocks+0x298/0x21e0 fs/ext4/mballoc.c:6140
 ext4_ext_map_blocks+0x1086/0x3640 fs/ext4/extents.c:4285
 ext4_map_blocks+0x704/0xf60 fs/ext4/inode.c:621
 ext4_alloc_file_blocks+0x285/0x6f0 fs/ext4/extents.c:4462
 ext4_fallocate+0x77e/0x1190 fs/ext4/extents.c:4757
 vfs_fallocate+0x378/0x3e0 fs/open.c:324
 do_vfs_ioctl+0x12e6/0x13a0 fs/ioctl.c:850
 __do_sys_ioctl fs/ioctl.c:869 [inline]
 __se_sys_ioctl+0x81/0x140 fs/ioctl.c:857
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:857
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff888237d1bf18 of 8 bytes by task 18057 on cpu 0:
 print_tickdevice+0x144/0x340 kernel/time/timer_list.c:204
 timer_list_show+0x79/0x180 kernel/time/timer_list.c:296
 seq_read_iter+0x612/0x8f0 fs/seq_file.c:272
 proc_reg_read_iter+0x114/0x180 fs/proc/inode.c:302
 call_read_iter include/linux/fs.h:2014 [inline]
 copy_splice_read+0x26b/0x4b0 fs/splice.c:364
 vfs_splice_read fs/splice.c:993 [inline]
 splice_direct_to_actor+0x28c/0x690 fs/splice.c:1069
 do_splice_direct+0x10d/0x190 fs/splice.c:1194
 do_sendfile+0x3c4/0x980 fs/read_write.c:1254
 __do_sys_sendfile64 fs/read_write.c:1322 [inline]
 __se_sys_sendfile64 fs/read_write.c:1308 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1308
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x7fffffffffffffff -> 0x0000006fcc7f1c06

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 18057 Comm: syz-executor.5 Not tainted 6.7.0-rc6-syzkaller-00010-g2cf4f94d8e86 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
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