Re: [Xen-devel] 2.6.29-rc8 pv_ops dom0 BUG / unable to handle kernel paging request

[Pasi Kärkkäinen <pasik@xxxxxx>]

On Sun, Mar 22, 2009 at 07:04:23PM +0200, Pasi Kärkkäinen wrote:
> On Sun, Mar 22, 2009 at 01:51:51PM +0200, Pasi Kärkkäinen wrote:
> > On Sat, Mar 21, 2009 at 09:28:55PM -0700, Jeremy Fitzhardinge wrote:
> > > Pasi Kärkkäinen wrote:
> > > >On Sun, Mar 22, 2009 at 12:50:31AM +0200, Pasi Kärkkäinen wrote:
> > > >  
> > > >>On Sat, Mar 21, 2009 at 10:16:52PM +0200, Pasi Kärkkäinen wrote:
> > > >>    
> > > >>>>Also, do you see this problem before you've started any other 
> > > >>>>domains?  
> > > >>>>Or does it only happen once you've run a domU (or only while a domU 
> > > >>>>is 
> > > >>>>running)?
> > > >>>>
> > > >>>>        
> > > >>>I'm not running any other domains.. Only dom0 is running.
> > > >>>
> > > >>>Steps to reproduce this BUG on my pv_ops dom0 testbox:
> > > >>>
> > > >>>1) Reboot the box to pv_ops dom0 kernel
> > > >>>2) Login to dom0 via ssh
> > > >>>3) Start kernel compilation on dom0 (make bzImage && make modules)
> > > >>>4) Wait some minutes and pv_ops dom0 kernel BUGs
> > > >>>
> > > >>>So no other domains has been or is running when this happens..
> > > >>>
> > > >>>I'll try disabling CONFIG_HIGHPTE now, and see if that makes any 
> > > >>>difference.
> > > >>>
> > > >>>      
> > > >>CONFIG_HIGHPTE=y and pv_ops dom0 survives up for maybe 30 mins, and then
> > > >>BUGs (during kernel compilation):
> > > >>http://pasik.reaktio.net/xen/pv_ops-dom0-debug/pv_ops-dom0-bootlog-22-xen331-linux-2.6.29-rc8-bug-with-highpte.txt
> > > >>
> > > >>
> > > >>CONFIG_HIGHPTE=n and I get BUG during system startup when udev is 
> > > >>started:
> > > >>http://pasik.reaktio.net/xen/pv_ops-dom0-debug/pv_ops-dom0-bootlog-23-xen331-linux-2.6.29-rc8-bug-no-highpte.txt
> > > >>
> > > >>Starting udev: BUG: unable to handle kernel paging request at 70007823
> > > >>IP: [<e30ce245>] pdc_common_ops+0x171/0xfffffcfe [sata_promise]
> > > >>*pdpt = 000000005f781001 
> > > >>Oops: 0002 [#1] SMP 
> > > >>
> > > >>So yeah..  with CONFIG_HIGHPTE=n it seems to happen when sata_promise 
> > > >>is 
> > > >>loaded.. What should I try next? 
> > > >>    
> > > >
> > > >Actually it's not only sata_promise. I tried 2 more times with the
> > > >CONFIG_HIGHPTE=n pv_ops dom0 kernel:
> > > >
> > > >http://pasik.reaktio.net/xen/pv_ops-dom0-debug/pv_ops-dom0-bootlog-23-xen331-linux-2.6.29-rc8-bug-no-highpte.txt
> > > >http://pasik.reaktio.net/xen/pv_ops-dom0-debug/pv_ops-dom0-bootlog-23-xen331-linux-2.6.29-rc8-bug-no-highpte-2.txt
> > > >http://pasik.reaktio.net/xen/pv_ops-dom0-debug/pv_ops-dom0-bootlog-23-xen331-linux-2.6.29-rc8-bug-no-highpte-3.txt
> > > >
> > > >BUG: unable to handle kernel paging request at a536462c
> > > >IP: [<e30f4278>] classes+0x688/0xfffffa30 [parport]
> > > >*pdpt = 000000005f759001 
> > > >Oops: 0002 [#1] SMP 
> > > >  
> > > 
> > > Hm, OK.  Something is clearly drastically amiss.  I'll try to repro.
> > > 
> > 
> > Actually it seems CONFIG_HIGHPTE=n kernel fails also on baremetal:
> > http://pasik.reaktio.net/xen/pv_ops-dom0-debug/pv_ops-dom0-bootlog-24-baremetal-2.6.29-rc8-bug-no-highpte.txt
> > 
> > Starting udev: invalid opcode: 0000 [#1] SMP 
> > 
> > Summary:
> > CONFIG_HIGHPTE=n: both dom0 and baremetal fail during system startup when 
> > udev is started
> > CONFIG_HIGHPTE=y: baremetal works OK, dom0 fails with BUG after around 30 
> > mins of kernel compilation
> > 
> 
> Please ignore this summary, there was something wrong with my kernel builds or
> something. 
> 
> I'll post new summary soon when I'm finished with testing. 
> 

Ok, I did new fresh kernel+modules builds and re-tested everything.

New summary:
CONFIG_HIGHPTE=n: both dom0 and baremetal work OK, both survive kernel 
compilation.
CONFIG_HIGHPTE=y: baremetal works OK and survives kernel compilation, but dom0 
fails with BUG after around 20-30 mins of kernel compilation

latest BUG with CONFIG_HIGHPTE=y with dom0 kernel:
http://pasik.reaktio.net/xen/pv_ops-dom0-debug/pv_ops-dom0-bootlog-25-xen331-linux-2.6.29-rc8-bug-with-highpte.txt

(XEN) mm.c:2006:d0 Bad type (saw 28000001 != exp e0000000) for mfn 57f2f (pfn 
2892f)
(XEN) mm.c:707:d0 Error getting mfn 57f2f (pfn 2892f) from L1 entry 
0000000057f2f063 for dom0
(XEN) mm.c:3640:d0 ptwr_emulate: could not get_page_from_l1e()
BUG: unable to handle kernel paging request at c020bc80
IP: [<c0405d23>] xen_set_pte+0x8c/0x96
*pdpt = 000000003c984001 
Oops: 0003 [#1] SMP 

I tested all combinations multiple times now, and the results were consistent. 

Another BUG with dom0 with CONFIG_HIGHPTE=y:
http://pasik.reaktio.net/xen/pv_ops-dom0-debug/pv_ops-dom0-bootlog-25-xen331-linux-2.6.29-rc8-bug-with-highpte-2.txt

(XEN) mm.c:2006:d0 Bad type (saw 28000001 != exp e0000000) for mfn 4c1e1 (pfn 
347e1)
(XEN) mm.c:707:d0 Error getting mfn 4c1e1 (pfn 347e1) from L1 entry 
000000004c1e1063 for dom0
(XEN) mm.c:3640:d0 ptwr_emulate: could not get_page_from_l1e()
BUG: unable to handle kernel paging request at c020bc80
IP: [<c0405d23>] xen_set_pte+0x8c/0x96
*pdpt = 000000003c984001 
Oops: 0003 [#1] SMP 

-- Pasi

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