[moderation] [kernel?] KCSAN: data-race in collect_posix_cputimers / run_posix_cpu_timers (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: e5b3efbe1ab1 Merge tag 'probes-fixes-v6.10-rc4' of git://g..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1371d261980000
kernel config: https://syzkaller.appspot.com/x/.config?x=704451bc2941bcb0
dashboard link: https://syzkaller.appspot.com/bug?extid=2224b81350eb7e28cf93
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [anna-...@linutronix.de fred...@kernel.org linux-...@vger.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/aba434953b89/disk-e5b3efbe.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6c615db72106/vmlinux-e5b3efbe.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ec51cef20784/bzImage-e5b3efbe.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2224b8...@syzkaller.appspotmail.com

kthread+0x1d1/0x210 kernel/kthread.c:389
ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>
==================================================================
BUG: KCSAN: data-race in collect_posix_cputimers / run_posix_cpu_timers

write to 0xffff8881046257c8 of 8 bytes by task 12096 on cpu 0:
collect_posix_cputimers+0x4e7/0x500 kernel/time/posix-cpu-timers.c:865
check_process_timers kernel/time/posix-cpu-timers.c:1001 [inline]
handle_posix_cpu_timers kernel/time/posix-cpu-timers.c:1352 [inline]
posix_cpu_timers_work+0x456/0x950 kernel/time/posix-cpu-timers.c:1169
task_work_run+0x13a/0x1a0 kernel/task_work.c:180
get_signal+0xeee/0x1080 kernel/signal.c:2681
arch_do_signal_or_restart+0x95/0x4b0 arch/x86/kernel/signal.c:310
exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
__syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
syscall_exit_to_user_mode+0x59/0x130 kernel/entry/common.c:218
do_syscall_64+0xd6/0x1c0 arch/x86/entry/common.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881046257c8 of 8 bytes by interrupt on cpu 1:
task_cputimers_expired kernel/time/posix-cpu-timers.c:1099 [inline]
fastpath_timer_check kernel/time/posix-cpu-timers.c:1151 [inline]
run_posix_cpu_timers+0x28a/0x310 kernel/time/posix-cpu-timers.c:1451
update_process_times+0x15f/0x180 kernel/time/timer.c:2492
tick_sched_handle kernel/time/tick-sched.c:276 [inline]
tick_nohz_handler+0x250/0x2d0 kernel/time/tick-sched.c:297
__run_hrtimer kernel/time/hrtimer.c:1687 [inline]
__hrtimer_run_queues+0x20d/0x5e0 kernel/time/hrtimer.c:1751
hrtimer_interrupt+0x210/0x7b0 kernel/time/hrtimer.c:1813
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

value changed: 0x0000004b8e54ab34 -> 0xffffffffffffffff

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 12097 Comm: syz-executor.2 Not tainted 6.10.0-rc4-syzkaller-00052-ge5b3efbe1ab1 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
==================================================================


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