syzbot

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BUG: KCSAN: data-race in print_cpu / tick_nohz_stop_idle

read-write to 0xffff888237d20270 of 8 bytes by interrupt on cpu 1:
 tick_sched_flag_clear kernel/time/tick-sched.c:201 [inline]
 tick_nohz_stop_idle+0xd0/0x110 kernel/time/tick-sched.c:739
 tick_nohz_irq_enter kernel/time/tick-sched.c:1528 [inline]
 tick_irq_enter+0xa2/0x150 kernel/time/tick-sched.c:1554
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
 sysvec_apic_timer_interrupt+0x66/0x80 arch/x86/kernel/apic/apic.c:1049
 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:699
 cpuidle_enter_state+0xc5/0x260 drivers/cpuidle/cpuidle.c:268
 cpuidle_enter+0x40/0x70 drivers/cpuidle/cpuidle.c:389
 call_cpuidle kernel/sched/idle.c:155 [inline]
 cpuidle_idle_call kernel/sched/idle.c:230 [inline]
 do_idle+0x192/0x230 kernel/sched/idle.c:325
 cpu_startup_entry+0x25/0x30 kernel/sched/idle.c:423
 start_secondary+0x96/0xa0 arch/x86/kernel/smpboot.c:315
 common_startup_64+0x12c/0x137

read to 0xffff888237d20270 of 8 bytes by task 11327 on cpu 0:
 print_cpu+0x404/0x670 kernel/time/timer_list.c:156
 timer_list_show+0x115/0x180 kernel/time/timer_list.c:295
 seq_read_iter+0x2d1/0x930 fs/seq_file.c:230
 proc_reg_read_iter+0x118/0x190 fs/proc/inode.c:299
 copy_splice_read+0x383/0x5b0 fs/splice.c:365
 do_splice_read fs/splice.c:985 [inline]
 splice_direct_to_actor+0x269/0x670 fs/splice.c:1089
 do_splice_direct_actor fs/splice.c:1207 [inline]
 do_splice_direct+0xd7/0x150 fs/splice.c:1233
 do_sendfile+0x398/0x660 fs/read_write.c:1363
 __do_sys_sendfile64 fs/read_write.c:1424 [inline]
 __se_sys_sendfile64 fs/read_write.c:1410 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1410
 x64_sys_call+0xfbd/0x2dc0 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: 0x0000000000000035 -> 0x0000000000000030

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 11327 Comm: syz.1.2700 Not tainted 6.14.0-rc7-syzkaller-00050-gfc444ada1310 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
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