[moderation] [kernel?] KCSAN: data-race in tick_nohz_handler / tick_nohz_handler

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Mar 12, 2024, 4:04:20 PMMar 12
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Hello,

syzbot found the following issue on:

HEAD commit: 855684c7d938 Merge tag 'x86_tdx_for_6.9' of git://git.kern..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13317749180000
kernel config: https://syzkaller.appspot.com/x/.config?x=4984a7e0e4b69c26
dashboard link: https://syzkaller.appspot.com/bug?extid=6ba4d2cbe64c744dd151
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [fred...@kernel.org linux-...@vger.kernel.org mi...@kernel.org tg...@linutronix.de]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/e47477ed6466/disk-855684c7.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d9ad3879b897/vmlinux-855684c7.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c8b609ab461e/bzImage-855684c7.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+6ba4d2...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in tick_nohz_handler / tick_nohz_handler

read to 0xffffffff86524f30 of 4 bytes by interrupt on cpu 1:
tick_sched_do_timer kernel/time/tick-sched.c:220 [inline]
tick_nohz_handler+0x3d/0x2d0 kernel/time/tick-sched.c:287
__run_hrtimer kernel/time/hrtimer.c:1692 [inline]
__hrtimer_run_queues+0x214/0x5e0 kernel/time/hrtimer.c:1756
hrtimer_interrupt+0x210/0x7b0 kernel/time/hrtimer.c:1818
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1032 [inline]
__sysvec_apic_timer_interrupt+0x5c/0x1a0 arch/x86/kernel/apic/apic.c:1049
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
sysvec_apic_timer_interrupt+0x32/0x80 arch/x86/kernel/apic/apic.c:1043
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702

write to 0xffffffff86524f30 of 4 bytes by interrupt on cpu 0:
tick_sched_do_timer kernel/time/tick-sched.c:224 [inline]
tick_nohz_handler+0x2bc/0x2d0 kernel/time/tick-sched.c:287
__run_hrtimer kernel/time/hrtimer.c:1692 [inline]
__hrtimer_run_queues+0x214/0x5e0 kernel/time/hrtimer.c:1756
hrtimer_interrupt+0x210/0x7b0 kernel/time/hrtimer.c:1818
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1032 [inline]
__sysvec_apic_timer_interrupt+0x5c/0x1a0 arch/x86/kernel/apic/apic.c:1049
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
sysvec_apic_timer_interrupt+0x6e/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:86 [inline]
acpi_safe_halt+0x21/0x30 drivers/acpi/processor_idle.c:112
acpi_idle_do_entry+0x1d/0x30 drivers/acpi/processor_idle.c:573
acpi_idle_enter+0x96/0xb0 drivers/acpi/processor_idle.c:707
cpuidle_enter_state+0xd4/0x270 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:236 [inline]
do_idle+0x195/0x230 kernel/sched/idle.c:332
cpu_startup_entry+0x25/0x30 kernel/sched/idle.c:430
rest_init+0xf3/0x100 init/main.c:730
arch_call_rest_init+0x9/0x10 init/main.c:831
start_kernel+0x57c/0x5e0 init/main.c:1077
x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:555
x86_64_start_kernel+0x94/0xa0 arch/x86/kernel/head64.c:536
secondary_startup_64_no_verify+0x15f/0x16b

value changed: 0xffffffff -> 0x00000001

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.8.0-syzkaller-01185-g855684c7d938 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
==================================================================


---
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