soft lockup detected in acpi_processor_idle() -- false positive?

soft lockup detected in acpi_processor_idle() -- false positive?

[Dominik Brodowski]

Latest git, fresh after resuming from suspend-to-disk (in-kernel variant):

[4294914.586000] Restarting tasks... done
[4294922.657000] BUG: soft lockup detected on CPU#0!
[4294922.657000] 
[4294922.657000] Pid: 0, comm:              swapper
[4294922.657000] EIP: 0060:[<f003084c>] CPU: 0
[4294922.657000] EIP is at acpi_processor_idle+0x1f3/0x2d5 [processor]
[4294922.657000]  EFLAGS: 00000282    Not tainted  (2.6.15)
[4294922.657000] EAX: fffff000 EBX: 005543a8 ECX: 00000000 EDX: 00000000
[4294922.657000] ESI: edcc3064 EDI: edcc2f60 EBP: c041cfdc DS: 007b ES: 007b
[4294922.657000] CR0: 8005003b CR2: 080c3000 CR3: 2d530000 CR4: 000006d0


As acpi_processor_idle doesn't take any locks AFAIK, it seems to me to be a
false positive -- or do I miss something obvious?

	Dominik

Re: soft lockup detected in acpi_processor_idle() -- false positive?

[Rafael J. Wysocki]

On Thursday, 12 January 2006 19:43, Dominik Brodowski wrote:
> Latest git, fresh after resuming from suspend-to-disk (in-kernel variant):
> 
> [4294914.586000] Restarting tasks... done
> [4294922.657000] BUG: soft lockup detected on CPU#0!
> [4294922.657000] 
> [4294922.657000] Pid: 0, comm:              swapper
> [4294922.657000] EIP: 0060:[<f003084c>] CPU: 0
> [4294922.657000] EIP is at acpi_processor_idle+0x1f3/0x2d5 [processor]
> [4294922.657000]  EFLAGS: 00000282    Not tainted  (2.6.15)
> [4294922.657000] EAX: fffff000 EBX: 005543a8 ECX: 00000000 EDX: 00000000
> [4294922.657000] ESI: edcc3064 EDI: edcc2f60 EBP: c041cfdc DS: 007b ES: 007b
> [4294922.657000] CR0: 8005003b CR2: 080c3000 CR3: 2d530000 CR4: 000006d0
> 
> 
> As acpi_processor_idle doesn't take any locks AFAIK, it seems to me to be a
> false positive -- or do I miss something obvious?

I think it's a false-positive.

This "soft lockup" message has been appearing for me for quite some time now
(actually since the softlockup patch made it into -mm ;-)), in a
non-reproducible manner, but I haven't been able to nail it down.

Still, I thought it was x86-64-specific, but your machine is an i386,
so there's more to it, apparently.  Probably there's missing
touch_softlockup_watchdog() somewhere, or the timer .suspend()/.resume()
routines need some additional review.

Greetings,
Rafael

Re: soft lockup detected in acpi_processor_idle() -- false positive?

[Shaohua Li]

On Thu, 2006-01-12 at 20:54 +0100, Rafael J. Wysocki wrote:
> On Thursday, 12 January 2006 19:43, Dominik Brodowski wrote:
> > Latest git, fresh after resuming from suspend-to-disk (in-kernel variant):
> > 
> > [4294914.586000] Restarting tasks... done
> > [4294922.657000] BUG: soft lockup detected on CPU#0!
> > [4294922.657000] 
> > [4294922.657000] Pid: 0, comm:              swapper
> > [4294922.657000] EIP: 0060:[<f003084c>] CPU: 0
> > [4294922.657000] EIP is at acpi_processor_idle+0x1f3/0x2d5 [processor]
> > [4294922.657000]  EFLAGS: 00000282    Not tainted  (2.6.15)
> > [4294922.657000] EAX: fffff000 EBX: 005543a8 ECX: 00000000 EDX: 00000000
> > [4294922.657000] ESI: edcc3064 EDI: edcc2f60 EBP: c041cfdc DS: 007b ES: 007b
> > [4294922.657000] CR0: 8005003b CR2: 080c3000 CR3: 2d530000 CR4: 000006d0
> > 
> > 
> > As acpi_processor_idle doesn't take any locks AFAIK, it seems to me to be a
> > false positive -- or do I miss something obvious?
> 
> I think it's a false-positive.
> 
> This "soft lockup" message has been appearing for me for quite some time now
> (actually since the softlockup patch made it into -mm ;-)), in a
> non-reproducible manner, but I haven't been able to nail it down.
> 
> Still, I thought it was x86-64-specific, but your machine is an i386,
> so there's more to it, apparently.  Probably there's missing
> touch_softlockup_watchdog() somewhere, or the timer .suspend()/.resume()
> routines need some additional review.
I got some similar reports for S3:
http://bugzilla.kernel.org/show_bug.cgi?id=5825
I guess x86-64 lacks .suspend/.resume for timer. Last time I looked at
such issue in ia32, and I fixed it, but I didn't fix x86-64.

Thanks,
Shaohua

Re: soft lockup detected in acpi_processor_idle() -- false positive?

[Rafael J. Wysocki]

On Friday, 13 January 2006 01:55, Shaohua Li wrote:
> On Thu, 2006-01-12 at 20:54 +0100, Rafael J. Wysocki wrote:
> > On Thursday, 12 January 2006 19:43, Dominik Brodowski wrote:
> > > Latest git, fresh after resuming from suspend-to-disk (in-kernel variant):
> > > 
> > > [4294914.586000] Restarting tasks... done
> > > [4294922.657000] BUG: soft lockup detected on CPU#0!
> > > [4294922.657000] 
> > > [4294922.657000] Pid: 0, comm:              swapper
> > > [4294922.657000] EIP: 0060:[<f003084c>] CPU: 0
> > > [4294922.657000] EIP is at acpi_processor_idle+0x1f3/0x2d5 [processor]
> > > [4294922.657000]  EFLAGS: 00000282    Not tainted  (2.6.15)
> > > [4294922.657000] EAX: fffff000 EBX: 005543a8 ECX: 00000000 EDX: 00000000
> > > [4294922.657000] ESI: edcc3064 EDI: edcc2f60 EBP: c041cfdc DS: 007b ES: 007b
> > > [4294922.657000] CR0: 8005003b CR2: 080c3000 CR3: 2d530000 CR4: 000006d0
> > > 
> > > 
> > > As acpi_processor_idle doesn't take any locks AFAIK, it seems to me to be a
> > > false positive -- or do I miss something obvious?
> > 
> > I think it's a false-positive.
> > 
> > This "soft lockup" message has been appearing for me for quite some time now
> > (actually since the softlockup patch made it into -mm ;-)), in a
> > non-reproducible manner, but I haven't been able to nail it down.
> > 
> > Still, I thought it was x86-64-specific, but your machine is an i386,
> > so there's more to it, apparently.  Probably there's missing
> > touch_softlockup_watchdog() somewhere, or the timer .suspend()/.resume()
> > routines need some additional review.
> I got some similar reports for S3:
> http://bugzilla.kernel.org/show_bug.cgi?id=5825
> I guess x86-64 lacks .suspend/.resume for timer.

No, it doesn't.  They are similar to i386 ones.

Greetings,
Rafael