Re: BUG: using smp_processor_id() during suspend with 2.6.25-rc8

[Rafael J. Wysocki]

On Tuesday, 8 of April 2008, Zdenek Kabelac wrote:
> 2008/4/8, Jiri Kosina <jkosina@xxxxxxx>:
> > On Tue, 8 Apr 2008, Rafael J. Wysocki wrote:
> >
> >  > > The mce resume is a sysdev.
> >  > > sysdevs were always supposed to run completely with interrupts off. If they
> >  > > don't anymore that's some kind of higher level resume code bug which you need
> >  > > to fix there, not hack around in the low level code.
> >  > They are executed with interrupts disabled, on one CPU.
> >
> >
> > So, any idea why mce_resume() -> mce_init() -> debug_smp_processor_id()
> >  triggers the warning? Apparently preempt_count is zero, irqs_disabled()
> >  returns false, and cpumask_of_cpu() is not equal to current->cpus_allowed.
> >
> >  So there clearly is a bug somewhere.
> >
> >
> >  > > Obviously turning on preemption anywhere around the machine check is
> >  > > fatal because it touches CPU state and if you reschedule you could
> >  > > switch to another CPU and change or access the wrong CPU's state.
> >  > FWIW, at the point when sysdevs are resumed we are single-threaded.
> >
> >
> > Is that really relevant here? We still could be switched over to another
> >  CPU, and that would break things.
> 
> 
> To avoid some mystery - these two warns precede warnings I've
> initially posted here - the reason why I've not posted also these 2
> kvm related warns is that kvm maintainers already know about this
> problem and said in the past that they will eventually fix them (If I
> remember correctly)
> 
> Warnings and bug looked somewhat unrelated - but I could be wrong and
> the mystery irq could be mangles in kvm....

Can you please test without the kvm, then?

> ACPI: Preparing to enter system sleep state S3
> Disabling non-boot CPUs ...
> kvm: disabling virtualization on CPU1
> ------------[ cut here ]------------
> WARNING: at arch/x86/kernel/smp_64.c:424 smp_call_function_single+0xea/0x100()
> Modules linked in: cpufreq_userspace tun i915 drm ipt_MASQUERADE
> iptable_nat nf_na
> t nf_conntrack_ipv4 xt_state nf_conntrack ipt_REJECT xt_tcpudp
> iptable_filter ip_tables x_tables bridge llc nfsd lockd nfs_acl auth
> _rpcgss exportfs autofs4 sunrpc binfmt_misc dm_mirror dm_log
> dm_multipath dm_mod uinput kvm_intel kvm snd_hda_intel snd_seq_oss snd
> _seq_midi_event snd_seq arc4 snd_seq_device snd_pcm_oss ecb
> snd_mixer_oss snd_pcm crypto_blkcipher video snd_timer iTCO_wdt
> cryptom
> gr crypto_algapi rtc_cmos iwl3945 sdhci mmc_core thinkpad_acpi snd
> mac80211 psmouse evdev iTCO_vendor_support rtc_core i2c_i801 out
> put rtc_lib soundcore snd_page_alloc e1000e sr_mod intel_agp battery
> ac backlight nvram serio_raw i2c_core cfg80211 cdrom button uh
> ci_hcd ohci_hcd ehci_hcd usbcore [last unloaded: microcode]
> Pid: 18951, comm: kstopmachine Not tainted 2.6.25-rc8 #32
> 
> Call Trace:
>  [warn_on_slowpath+95/144] warn_on_slowpath+0x5f/0x90
>  [vprintk+560/1136] ? vprintk+0x230/0x470
>  [hrtick_set+57/304] ? hrtick_set+0x39/0x130
>  [_end+108902941/2109239016] ? :kvm:decache_vcpus_on_cpu+0x65/0xe0
>  [smp_call_function_single+234/256] smp_call_function_single+0xea/0x100
>  [_end+109030358/2109239016] :kvm_intel:vmx_vcpu_decache+0x2e/0x40
>  [_end+108903005/2109239016] :kvm:decache_vcpus_on_cpu+0xa5/0xe0
>  [_end+108882341/2109239016] :kvm:hardware_disable+0x2d/0x40
>  [_end+108882503/2109239016] :kvm:kvm_cpu_hotplug+0x8f/0xe0
>  [notifier_call_chain+63/128] notifier_call_chain+0x3f/0x80
>  [raw_notifier_call_chain+17/32] raw_notifier_call_chain+0x11/0x20
>  [take_cpu_down+27/64] take_cpu_down+0x1b/0x40
>  [do_stop+328/576] do_stop+0x148/0x240
>  [do_stop+0/576] ? do_stop+0x0/0x240
>  [do_stop+0/576] ? do_stop+0x0/0x240
>  [kthread+73/144] kthread+0x49/0x90
>  [child_rip+10/18] child_rip+0xa/0x12
>  [restore_args+0/48] ? restore_args+0x0/0x30
>  [kthread+0/144] ? kthread+0x0/0x90
>  [child_rip+0/18] ? child_rip+0x0/0x12
> 
> ---[ end trace ca143223eefdc828 ]---
> CPU 1 is now offline
> lockdep: fixing up alternatives.
> SMP alternatives: switching to UP code
> CPU1 is down
> ------------[ cut here ]------------
> WARNING: at arch/x86/kernel/smp_64.c:424 smp_call_function_single+0xea/0x100()
> Modules linked in: cpufreq_userspace tun i915 drm ipt_MASQUERADE
> iptable_nat nf_na
> ECT xt_tcpudp iptable_filter ip_tables x_tables bridge llc nfsd lockd
> nfs_acl auth
> rror dm_log dm_multipath dm_mod uinput kvm_intel kvm snd_hda_intel
> snd_seq_oss snd
> cm_oss ecb snd_mixer_oss snd_pcm crypto_blkcipher video snd_timer
> iTCO_wdt cryptom
> thinkpad_acpi snd mac80211 psmouse evdev iTCO_vendor_support rtc_core
> i2c_i801 out
> d intel_agp battery ac backlight nvram serio_raw i2c_core cfg80211
> cdrom button uh
> microcode]
> Pid: 18791, comm: pm-suspend Not tainted 2.6.25-rc8 #32
> 
> Call Trace:
>  [warn_on_slowpath+95/144] warn_on_slowpath+0x5f/0x90
>  [_spin_unlock_irqrestore+69/144] ? _spin_unlock_irqrestore+0x45/0x90
>  [release_console_sem+535/560] ? release_console_sem+0x217/0x230
>  [vprintk+560/1136] ? vprintk+0x230/0x470
>  [_end+108902941/2109239016] ? :kvm:decache_vcpus_on_cpu+0x65/0xe0
>  [smp_call_function_single+234/256] smp_call_function_single+0xea/0x100
>  [_end+109030358/2109239016] :kvm_intel:vmx_vcpu_decache+0x2e/0x40
>  [_end+108903005/2109239016] :kvm:decache_vcpus_on_cpu+0xa5/0xe0
>  [_end+108882341/2109239016] :kvm:hardware_disable+0x2d/0x40

This looks suspiciously.

Apparently, kvm_suspend() does something not entirely sane and that may
very well confuse things later on.

>  [_end+108882595/2109239016] :kvm:kvm_suspend+0xb/0x10
>  [sysdev_suspend+209/560] sysdev_suspend+0xd1/0x230
>  [device_power_down+177/256] device_power_down+0xb1/0x100
>  [suspend_devices_and_enter+300/416] suspend_devices_and_enter+0x12c/0x1a0
>  [enter_state+326/464] enter_state+0x146/0x1d0
>  [state_store+186/256] state_store+0xba/0x100
>  [kobj_attr_store+23/32] kobj_attr_store+0x17/0x20
>  [sysfs_write_file+202/320] sysfs_write_file+0xca/0x140
>  [vfs_write+203/368] vfs_write+0xcb/0x170
>  [sys_write+80/144] sys_write+0x50/0x90
>  [system_call_after_swapgs+123/128] system_call_after_swapgs+0x7b/0x80
> 
> ---[ end trace ca143223eefdc828 ]---
> Extended CMOS year: 2000

Thanks,
Rafael
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