syzbot


KCSAN: data-race in collect_posix_cputimers / run_posix_cpu_timers

Status: auto-closed as invalid on 2022/09/19 15:12
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 112d, last: 112d

Sample crash report:
==================================================================
BUG: KCSAN: data-race in collect_posix_cputimers / run_posix_cpu_timers

write to 0xffff88813e8157c8 of 8 bytes by task 11119 on cpu 1:
 collect_posix_cputimers+0x4ae/0x4d0 kernel/time/posix-cpu-timers.c:864
 check_process_timers+0x134/0x810 kernel/time/posix-cpu-timers.c:1000
 handle_posix_cpu_timers kernel/time/posix-cpu-timers.c:1296 [inline]
 posix_cpu_timers_work+0x351/0x560 kernel/time/posix-cpu-timers.c:1165
 task_work_run+0x8e/0x110 kernel/task_work.c:177
 get_signal+0xeca/0x1020 kernel/signal.c:2634
 arch_do_signal_or_restart+0x87/0x2d0 arch/x86/kernel/signal.c:869
 exit_to_user_mode_loop+0x78/0x130 kernel/entry/common.c:166
 exit_to_user_mode_prepare kernel/entry/common.c:201 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline]
 syscall_exit_to_user_mode+0x6a/0x90 kernel/entry/common.c:294
 do_syscall_64+0x37/0x70 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff88813e8157c8 of 8 bytes by interrupt on cpu 0:
 task_cputimers_expired kernel/time/posix-cpu-timers.c:1098 [inline]
 fastpath_timer_check kernel/time/posix-cpu-timers.c:1150 [inline]
 run_posix_cpu_timers+0x283/0x300 kernel/time/posix-cpu-timers.c:1393
 update_process_times+0x10e/0x120 kernel/time/timer.c:1846
 tick_sched_handle kernel/time/tick-sched.c:243 [inline]
 tick_sched_timer+0x246/0x2d0 kernel/time/tick-sched.c:1480
 __run_hrtimer+0x132/0x420 kernel/time/hrtimer.c:1685
 __hrtimer_run_queues kernel/time/hrtimer.c:1749 [inline]
 hrtimer_interrupt+0x36e/0xa70 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1095 [inline]
 __sysvec_apic_timer_interrupt+0xa3/0x250 arch/x86/kernel/apic/apic.c:1112
 sysvec_apic_timer_interrupt+0x88/0xb0 arch/x86/kernel/apic/apic.c:1106
 asm_sysvec_apic_timer_interrupt+0x16/0x20
 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
 _raw_spin_unlock_irq+0x29/0x50 kernel/locking/spinlock.c:202
 spin_unlock_irq include/linux/spinlock.h:399 [inline]
 do_signal_stop+0x4b5/0x5f0 kernel/signal.c:2457
 get_signal+0x61d/0x1020 kernel/signal.c:2809
 arch_do_signal_or_restart+0x87/0x2d0 arch/x86/kernel/signal.c:869
 exit_to_user_mode_loop+0x78/0x130 kernel/entry/common.c:166
 exit_to_user_mode_prepare kernel/entry/common.c:201 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline]
 syscall_exit_to_user_mode+0x6a/0x90 kernel/entry/common.c:294
 do_syscall_64+0x37/0x70 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x0000000000000000 -> 0x0000000003b85681

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 11084 Comm: syz-executor.0 Not tainted 5.19.0-syzkaller-13930-g7ebfc85e2cd7-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
==================================================================

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-upstream-kcsan-gce 2022/08/15 15:02 upstream 7ebfc85e2cd7 8dfcaa3d .config log report info KCSAN: data-race in collect_posix_cputimers / run_posix_cpu_timers
* Struck through repros no longer work on HEAD.