syzbot


KCSAN: data-race in next_expiry_recalc / update_process_times

Status: moderation: reported on 2024/03/19 01:56
Subsystems: kernel
[Documentation on labels]
Reported-by: syzbot+bd8e292fa022f9ff2e9f@syzkaller.appspotmail.com
First crash: 28d, last: 18d

Sample crash report:
==================================================================
BUG: KCSAN: data-race in next_expiry_recalc / update_process_times

write to 0xffff888237d1ded8 of 8 bytes by interrupt on cpu 0:
 next_expiry_recalc+0x187/0x1e0 kernel/time/timer.c:1968
 __run_timers kernel/time/timer.c:2415 [inline]
 __run_timer_base+0x2ee/0x640 kernel/time/timer.c:2429
 timer_expire_remote+0x2f/0x40 kernel/time/timer.c:2181
 tmigr_handle_remote_cpu kernel/time/timer_migration.c:908 [inline]
 tmigr_handle_remote_up kernel/time/timer_migration.c:1000 [inline]
 __walk_groups kernel/time/timer_migration.c:488 [inline]
 tmigr_handle_remote+0x4ee/0x910 kernel/time/timer_migration.c:1061
 run_timer_softirq+0x5f/0x70 kernel/time/timer.c:2452
 __do_softirq+0xc8/0x285 kernel/softirq.c:554
 invoke_softirq kernel/softirq.c:428 [inline]
 __irq_exit_rcu kernel/softirq.c:633 [inline]
 irq_exit_rcu+0x3c/0x90 kernel/softirq.c:645
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
 sysvec_apic_timer_interrupt+0x73/0x80 arch/x86/kernel/apic/apic.c:1043
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
 __sanitizer_cov_trace_pc+0x46/0x70 kernel/kcov.c:212
 io_cqring_wait io_uring/io_uring.c:2639 [inline]
 __do_sys_io_uring_enter io_uring/io_uring.c:3708 [inline]
 __se_sys_io_uring_enter+0x1037/0x1820 io_uring/io_uring.c:3598
 __x64_sys_io_uring_enter+0x78/0x90 io_uring/io_uring.c:3598
 do_syscall_64+0xd3/0x1d0
 entry_SYSCALL_64_after_hwframe+0x6d/0x75

read to 0xffff888237d1ded8 of 8 bytes by interrupt on cpu 1:
 run_local_timers kernel/time/timer.c:2467 [inline]
 update_process_times+0x8a/0x180 kernel/time/timer.c:2485
 tick_sched_handle kernel/time/tick-sched.c:273 [inline]
 tick_nohz_handler+0x250/0x2d0 kernel/time/tick-sched.c:294
 __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+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:236 [inline]
 do_idle+0x195/0x230 kernel/sched/idle.c:332
 cpu_startup_entry+0x25/0x30 kernel/sched/idle.c:430
 start_secondary+0x94/0xa0 arch/x86/kernel/smpboot.c:313
 common_startup_64+0x12c/0x137

value changed: 0x00000000ffffc5c7 -> 0x00000000ffffc5c8

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 6.9.0-rc1-syzkaller-00178-g317c7bc0ef03 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
==================================================================

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/03/29 10:22 upstream 317c7bc0ef03 c52bcb23 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in next_expiry_recalc / update_process_times
2024/03/19 01:55 upstream f6cef5f8c37f baa80228 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in next_expiry_recalc / update_process_times
* Struck through repros no longer work on HEAD.