Re: [possible regression] 2.6.22 reiserfs/libata sporadically hangs on resume from hibernation

[Andrey Borzenkov <arvidjaar@mail.ru>]

On Sunday 01 July 2007, Rafael J. Wysocki wrote:
> On Saturday, 30 June 2007 23:34, Andrey Borzenkov wrote:
> > On Sunday 01 July 2007, Rafael J. Wysocki wrote:
> > > On Saturday, 30 June 2007 06:59, Andrey Borzenkov wrote:
> > > > Since 2.6.18 I do not have suspend to RAM; now I am starting to lose
> > > > suspend to disk :)
> > > >
> > > > Environment - vanilla kernel (2.6.22-rc6 currently + squashfs +
> > > > single pata_ali patch to switch off DMA on CD-ROM), single root on
> > > > reiserfs, libata with pata_ali driver.
> > > >
> > > > Until 2.6.22-rc I never had problems with hibernation. With 2.6.22-rc
> > > > system hung at least once in every rcX. Up to rc6 those lockups were
> > > > absolutely silent (black screen without reaction to any key). In rc6
> > > > I just got something different. After resume I got on screem:
> > > >
> > > > swsusp: Marking nosave pages: 000000000009f000-0000000000100000
> > > > swsusp: Basic memory bitmaps created
> > > > swsusp: Basic memory bitmaps freed
> > > >
> > > > After that it just sits there doing nothing. Ther was brief sound of
> > > > HDD but I suspect it was related more to power-on. System was
> > > > responding to power-on button press:
> > > >
> > > > ACPI Error (event-0305): No installed handler for fixed event
> > > > [00000002 20070125]
> > > >
> > > > And SysRq was functioning.
> > >
> > > That probably means that there's a deadlock somewhere in there.
> > >
> > > > Unfortunately I do not have serial console so I
> > > > copy manually stacks from several last screens of output; I have
> > > > tried to make a photo but right now my kbluetooth is refusing to work
> > > > at all so I cannot transfer them :( (but I suspect quality would be
> > > > too bad anyway)
> > > >
> > > > laptop_mode D
> > > > 	io_schedule+0xe/0x20
> > >
> > > Looks suspicious to me.  Can you identify what line of code this points
> > > to?
> >
> > If you could explain how to ...
>
> Michal has already done that. :-)
>
> [--snip--]
>
> > > I see you're using CFQ as the default IO scheduler.  Can you please
> > > switch to AS and see if that changes anything?
> >
> > Sure, but given that I have no idea how to reproduce the lockup, we may
> > never know whether it actually helped.
>
> Well, if the lockup never happens with AS, that will indicate something ...
>

I thought it is gone but it just happened again with 2.6.23-rc5. I thought I 
have been running AS but no, I did use CFQ. Now I definitely switched to AS 
default; let's see ...

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