syzbot

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BUG: KCSAN: data-race in print_cpu / tick_nohz_stop_idle

read-write to 0xffff888237d20540 of 8 bytes by interrupt on cpu 1:
 tick_nohz_stop_idle+0xaa/0x110
 tick_nohz_irq_enter kernel/time/tick-sched.c:1527 [inline]
 tick_irq_enter+0xa2/0x150 kernel/time/tick-sched.c:1553
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
 sysvec_apic_timer_interrupt+0x66/0x80 arch/x86/kernel/apic/apic.c:1043
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
 native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline]
 arch_safe_halt arch/x86/include/asm/irqflags.h:106 [inline]
 acpi_safe_halt+0x21/0x30 drivers/acpi/processor_idle.c:111
 acpi_idle_do_entry+0x1d/0x30 drivers/acpi/processor_idle.c:568
 acpi_idle_enter+0x96/0xb0 drivers/acpi/processor_idle.c:702
 cpuidle_enter_state+0xcf/0x270 drivers/cpuidle/cpuidle.c:267
 cpuidle_enter+0x40/0x70 drivers/cpuidle/cpuidle.c:388
 call_cpuidle kernel/sched/idle.c:155 [inline]
 cpuidle_idle_call kernel/sched/idle.c:230 [inline]
 do_idle+0x195/0x230 kernel/sched/idle.c:326
 cpu_startup_entry+0x25/0x30 kernel/sched/idle.c:424
 start_secondary+0x94/0xa0 arch/x86/kernel/smpboot.c:313
 common_startup_64+0x12c/0x137

read to 0xffff888237d20540 of 8 bytes by task 5845 on cpu 0:
 print_cpu+0x562/0x670 kernel/time/timer_list.c:165
 timer_list_show+0x115/0x180 kernel/time/timer_list.c:295
 seq_read_iter+0x65b/0x940 fs/seq_file.c:272
 proc_reg_read_iter+0x11e/0x190 fs/proc/inode.c:299
 copy_splice_read+0x3a4/0x5d0 fs/splice.c:365
 do_splice_read fs/splice.c:985 [inline]
 splice_direct_to_actor+0x26c/0x670 fs/splice.c:1089
 do_splice_direct_actor fs/splice.c:1207 [inline]
 do_splice_direct+0xd7/0x150 fs/splice.c:1233
 do_sendfile+0x3ab/0x950 fs/read_write.c:1295
 __do_sys_sendfile64 fs/read_write.c:1362 [inline]
 __se_sys_sendfile64 fs/read_write.c:1348 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1348
 x64_sys_call+0xed5/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x000000066c671cd3 -> 0x000000066c680fa6

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 5845 Comm: syz.2.560 Not tainted 6.11.0-rc2-syzkaller-00027-g6a0e38264012 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
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netlink: 8 bytes leftover after parsing attributes in process `syz.2.560'.
netlink: 16 bytes leftover after parsing attributes in process `syz.2.560'.