Messages in this thread | | | From | Dmitry Vyukov <> | Date | Tue, 11 Jan 2022 14:49:36 +0100 | Subject | Re: KCSAN: data-race in tick_nohz_stop_tick / tick_sched_timer |
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On Tue, 11 Jan 2022 at 14:41, Kaia Yadira <hypericumperforatum4444@gmail.com> wrote: > > Hello,
Hi Kaia, kvartet,
You started sending similarly looking reports around the same time. Please share what you are doing/why and what's your goal? The issue is that some of these reports may need some pre-moderation before dumping onto kernel mailing lists.
> When using Syzkaller to fuzz the latest Linux kernel, the following > crash was triggered. > > HEAD commit: a7904a538933 Linux 5.16-rc6 > git tree: upstream > console output: KCSAN: data-race in tick_nohz_stop_tick / tick_nohz_stop_tick > kernel config: https://paste.ubuntu.com/p/QB39MJKWKb/plain/ > Syzlang reproducer: https://paste.ubuntu.com/p/T25kYMrytM/plain/ > > If you fix this issue, please add the following tag to the commit: > > Reported-by: Hypericum <hypericumperforatum4444@gmail.com> > > I think there are two threads visiting the variable tick_do_timer_cpu > at kernel/time/tick-sched.c:191 and 872 without locking. > > reproducer log: https://paste.ubuntu.com/p/942c3QpFDJ/plain/ > report: > ================================================================== > BUG: KCSAN: data-race in tick_nohz_stop_tick / tick_sched_timer > > write to 0xffffffff85ebf1e0 of 4 bytes by task 0 on cpu 6: > tick_nohz_stop_tick+0xa5/0x410 kernel/time/tick-sched.c:873 > __tick_nohz_idle_stop_tick kernel/time/tick-sched.c:1062 [inline] > tick_nohz_idle_stop_tick+0xde/0x1a0 kernel/time/tick-sched.c:1083 > cpuidle_idle_call kernel/sched/idle.c:192 [inline] > do_idle+0xe3/0x250 kernel/sched/idle.c:306 > cpu_startup_entry+0x15/0x20 kernel/sched/idle.c:403 > secondary_startup_64_no_verify+0xb1/0xbb > > read to 0xffffffff85ebf1e0 of 4 bytes by interrupt on cpu 1: > tick_sched_do_timer kernel/time/tick-sched.c:187 [inline] > tick_sched_timer+0x41/0x210 kernel/time/tick-sched.c:1421 > __run_hrtimer+0x133/0x420 kernel/time/hrtimer.c:1685 > __hrtimer_run_queues kernel/time/hrtimer.c:1749 [inline] > hrtimer_interrupt+0x36e/0xa80 kernel/time/hrtimer.c:1811 > local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] > __sysvec_apic_timer_interrupt+0xa3/0x250 arch/x86/kernel/apic/apic.c:1103 > sysvec_apic_timer_interrupt+0x88/0xb0 arch/x86/kernel/apic/apic.c:1097 > asm_sysvec_apic_timer_interrupt+0x12/0x20 > native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline] > arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline] > default_idle+0xb/0x10 arch/x86/kernel/process.c:733 > default_idle_call+0x28/0xd0 kernel/sched/idle.c:112 > cpuidle_idle_call kernel/sched/idle.c:194 [inline] > do_idle+0xe8/0x250 kernel/sched/idle.c:306 > cpu_startup_entry+0x15/0x20 kernel/sched/idle.c:403 > secondary_startup_64_no_verify+0xb1/0xbb > > value changed: 0x00000006 -> 0xffffffff > > Reported by Kernel Concurrency Sanitizer on: > CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.16.0-rc8+ #11 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS > 1.13.0-1ubuntu1.1 04/01/2014 > ================================================================== > > -- > You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group. > To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-bugs+unsubscribe@googlegroups.com. > To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/CACDmwr_b0Z6JK2M6i6RZ4Qg3wb1uqG0NrybQ9mR2iw5QJT8XoA%40mail.gmail.com.
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