syzbot

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BUG: KCSAN: data-race in hrtimer_interrupt / print_tickdevice

write to 0xffff888237d17758 of 8 bytes by interrupt on cpu 1:
 hrtimer_interrupt+0x7d/0x460 kernel/time/hrtimer.c:1866
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline]
 __sysvec_apic_timer_interrupt+0x5f/0x1d0 arch/x86/kernel/apic/apic.c:1056
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0x6f/0x80 arch/x86/kernel/apic/apic.c:1050
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
 kcsan_setup_watchpoint+0x415/0x430 kernel/kcsan/core.c:705
 xas_next_entry include/linux/xarray.h:1729 [inline]
 next_uptodate_folio+0x164/0x890 mm/filemap.c:3553
 filemap_map_pages+0x798/0xab0 mm/filemap.c:3746
 do_fault_around mm/memory.c:5476 [inline]
 do_read_fault mm/memory.c:5509 [inline]
 do_fault mm/memory.c:5652 [inline]
 do_pte_missing mm/memory.c:4160 [inline]
 handle_pte_fault mm/memory.c:5997 [inline]
 __handle_mm_fault mm/memory.c:6140 [inline]
 handle_mm_fault+0x1332/0x2c00 mm/memory.c:6309
 faultin_page mm/gup.c:1193 [inline]
 __get_user_pages+0x102c/0x2050 mm/gup.c:1491
 populate_vma_page_range mm/gup.c:1929 [inline]
 __mm_populate+0x243/0x3a0 mm/gup.c:2032
 mm_populate include/linux/mm.h:3487 [inline]
 vm_mmap_pgoff+0x232/0x2e0 mm/util.c:584
 ksys_mmap_pgoff+0xc2/0x310 mm/mmap.c:607
 x64_sys_call+0x1602/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:10
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888237d17758 of 8 bytes by task 5900 on cpu 0:
 print_tickdevice+0x142/0x340 kernel/time/timer_list.c:208
 timer_list_show+0x6c/0x170 kernel/time/timer_list.c:300
 seq_read_iter+0x62a/0x940 fs/seq_file.c:272
 proc_reg_read_iter+0x10d/0x180 fs/proc/inode.c:299
 copy_splice_read+0x3c1/0x5f0 fs/splice.c:363
 do_splice_read fs/splice.c:979 [inline]
 splice_direct_to_actor+0x26c/0x680 fs/splice.c:1083
 do_splice_direct_actor fs/splice.c:1201 [inline]
 do_splice_direct+0xda/0x150 fs/splice.c:1227
 do_sendfile+0x380/0x650 fs/read_write.c:1370
 __do_sys_sendfile64 fs/read_write.c:1431 [inline]
 __se_sys_sendfile64 fs/read_write.c:1417 [inline]
 __x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1417
 x64_sys_call+0xb39/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000001299ce56e0 -> 0x0000001299d0a880

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 5900 Comm: syz.4.641 Not tainted 6.15.0-syzkaller-07774-g90b83efa6701 #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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