syzbot


KCSAN: data-race in next_expiry_recalc / update_process_times (2)

Status: upstream: reported on 2024/08/13 20:40
Subsystems: kernel
[Documentation on labels]
Reported-by: syzbot+bf285fcc0a048e028118@syzkaller.appspotmail.com
First crash: 29d, last: 14d
Discussions (2)
Title Replies (including bot) Last reply
[PATCH] timers: Annotate possible non critical data race of next_expiry 5 (5) 2024/09/04 10:08
[syzbot] [kernel?] KCSAN: data-race in next_expiry_recalc / update_process_times (2) 0 (1) 2024/08/13 20:40
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in next_expiry_recalc / update_process_times kernel 7 105d 177d 0/27 auto-obsoleted due to no activity on 2024/07/03 19:14

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

write to 0xffff888237c1de58 of 8 bytes by interrupt on cpu 1:
 next_expiry_recalc+0x187/0x1e0 kernel/time/timer.c:1967
 __run_timers kernel/time/timer.c:2414 [inline]
 __run_timer_base+0x2ee/0x640 kernel/time/timer.c:2428
 timer_expire_remote+0x2f/0x40 kernel/time/timer.c:2180
 tmigr_handle_remote_cpu kernel/time/timer_migration.c:930 [inline]
 tmigr_handle_remote_up kernel/time/timer_migration.c:1021 [inline]
 __walk_groups kernel/time/timer_migration.c:533 [inline]
 tmigr_handle_remote+0x4f6/0x940 kernel/time/timer_migration.c:1080
 run_timer_softirq+0x5f/0x70 kernel/time/timer.c:2451
 handle_softirqs+0xc3/0x280 kernel/softirq.c:554
 __do_softirq kernel/softirq.c:588 [inline]
 invoke_softirq kernel/softirq.c:428 [inline]
 __irq_exit_rcu kernel/softirq.c:637 [inline]
 irq_exit_rcu+0x3e/0x90 kernel/softirq.c:649
 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
 syscall_enter_from_user_mode_work include/linux/entry-common.h:165 [inline]
 syscall_enter_from_user_mode include/linux/entry-common.h:198 [inline]
 do_syscall_64+0x9a/0x1c0 arch/x86/entry/common.c:79
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888237c1de58 of 8 bytes by interrupt on cpu 0:
 run_local_timers kernel/time/timer.c:2466 [inline]
 update_process_times+0x8a/0x180 kernel/time/timer.c:2484
 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:1689 [inline]
 __hrtimer_run_queues+0x20d/0x5e0 kernel/time/hrtimer.c:1753
 hrtimer_interrupt+0x210/0x7b0 kernel/time/hrtimer.c:1815
 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: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:702
 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:230 [inline]
 do_idle+0x195/0x230 kernel/sched/idle.c:326
 cpu_startup_entry+0x25/0x30 kernel/sched/idle.c:424
 rest_init+0xef/0xf0 init/main.c:747
 start_kernel+0x581/0x5e0 init/main.c:1103
 x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:507
 x86_64_start_kernel+0x9a/0xa0 arch/x86/kernel/head64.c:488
 common_startup_64+0x12c/0x137

value changed: 0x00000000ffffa73f -> 0x00000000ffffa740

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.11.0-rc5-syzkaller-00057-g86987d84b968 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
==================================================================

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/08/28 23:30 upstream 86987d84b968 ef3de9e8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in next_expiry_recalc / update_process_times
2024/08/13 19:24 upstream 6b4aa469f049 f21a18ca .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.