Lock-up on PPC64

Lock-up on PPC64

[malc]

Hello,

Benjamin Herrenschmidt asked to re-report this issue to linuxppc-dev and
here it is.

[original LKML message http://lkml.org/lkml/2008/12/21/105]

Synopsis

Plain/non-root userspace application which doesn't interface with
any weird out-of/in-tree drivers manages to lock-up a PS3 machine
running Linux.

The application in question is Mono VM running mcs.exe (C# compiler)
which tries to compile particular file, distribution is Yellow Dog Linux
6.0 with either stock (2.6.23.x) or custom compiled (2.6.27) 64bit kernel.


Symptoms are as follows (interaction is done via ssh from another
machine):

$ make
... lots of stdout/err messages
... eventually an error message

Eventually the ssh session terminates, PS3 is still pingable but
impossible to connect to, attaching keyboard and trying magic SysRq
doesn't work, typing keys into login: prompt works (as in - the terminal
shows keys that were pressed, but after hittiing enter the carret is
advanced and nothing happens, hitting random keys doesn't yield anything
either)

There's a bug in Mono bugzilla which describes exactly the same problem,
but it appears as if reporters machine continued working after hitting
the problem. https://bugzilla.novell.com/show_bug.cgi?id=414845
The reporter aslo managed to create minimal reproducible test case
(so that running `MONO_PATH=... .../mono .../mcs.exe prob.cs' kills
  this PS3 just as well)

Any pointers to what can be done to further debug this would be greatly
appreciated.

[ends here]

Unfortunatelly reproducing requires building Mono from sources.

Mono 2.0.1 can only be built in 32bit mode and still exhibits the same
(locking-up behavior):
 http://ftp.novell.com/pub/mono/sources/mono/mono-2.0.1.tar.bz2

Or the one from the SVN, instructions are at:
http://mono-project.com/AnonSVN
(Configured with: `CC='gcc -m64' ./configure' (never tried 32bit build))

Unfortunatelly the only PPC64 machine i have access to that's running
Linux is a PS3 so i can not confirm/deny the reproducibility on other
PPC64's.

P.S. FWIW custom 2.6.27 = ps3_defconfig + enabled netconsole.

-- 
mailto:av1474@comtv.ru

Re: Lock-up on PPC64

[malc]

On Thu, 25 Dec 2008, Benjamin Herrenschmidt wrote:

> On Wed, 2008-12-24 at 03:08 +0300, malc@pulsesoft.com wrote:
>> Ken Moffat <zarniwhoop@ntlworld.com> writes:
>>
>>> On Tue, Dec 23, 2008 at 06:04:45AM +0300, malc@pulsesoft.com wrote:

[..snip..]

>>
>> Thanks for the reference, but i'm sure, now more than ever, that bad
>> memory has nothing to do with it, all signs are there that kernel is
>> confused by the way signals are (mis)used by Mono.
>
> It shouldn't be but I agree with you, it smells bad. Can you report that
> again on the linuxppc-dev@ozlabs.org mailing list ? Along with
> instructions to d/l, install & run the minimum repro-case ? I'll try to
> give it a go on different ppc64 machines as soon as I'm over my upcoming
> xmas hangover :-) If it appears to be ps3 specific, we can work with
> Geoff Levand (PS3 maintainer for Sony) to try to identify the root cause
> and fix it.

I've posted a message to linuxppc-dev via gmane, but AFAICS it never made
it there. Anyhow, here's another try:

Mono can be obtained from:
http://ftp.novell.com/pub/mono/sources/mono/mono-2.0.1.tar.bz2

Although 2.0.1 only supports ppc32 the problem is still reproducible.

Now to the Christmas cheer, i've tried v2.6.28 and couldn't help but
notice that the problem is gone, bisecting v2.6.27 (which funnily i
had to mark good) to v2.6.28 (which has to be marked bad) wasn't fun
but eventually converged at ab598b6680f1e74c267d1547ee352f3e1e530f89

commit ab598b6680f1e74c267d1547ee352f3e1e530f89
Author: Paul Mackerras <paulus@samba.org>
Date:   Sun Nov 30 11:49:45 2008 +0000

     powerpc: Fix system calls on Cell entered with XER.SO=1

Now the lock-up is gone, however the code never exercises the path
taken during the lock-up so i guess it, at least, deserves a better
look by PPC64 care takers.

-- 
mailto:av1474@comtv.ru

Re: Lock-up on PPC64

[Michael Ellerman]

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On Sun, 2008-12-28 at 03:45 +0300, malc wrote:
> On Thu, 25 Dec 2008, Benjamin Herrenschmidt wrote:
> 
> > On Wed, 2008-12-24 at 03:08 +0300, malc@pulsesoft.com wrote:
> >> Ken Moffat <zarniwhoop@ntlworld.com> writes:
> >>
> >>> On Tue, Dec 23, 2008 at 06:04:45AM +0300, malc@pulsesoft.com wrote:
> 
> [..snip..]
> 
> >>
> >> Thanks for the reference, but i'm sure, now more than ever, that bad
> >> memory has nothing to do with it, all signs are there that kernel is
> >> confused by the way signals are (mis)used by Mono.
> >
> > It shouldn't be but I agree with you, it smells bad. Can you report that
> > again on the linuxppc-dev@ozlabs.org mailing list ? Along with
> > instructions to d/l, install & run the minimum repro-case ? I'll try to
> > give it a go on different ppc64 machines as soon as I'm over my upcoming
> > xmas hangover :-) If it appears to be ps3 specific, we can work with
> > Geoff Levand (PS3 maintainer for Sony) to try to identify the root cause
> > and fix it.
> 
> I've posted a message to linuxppc-dev via gmane, but AFAICS it never made
> it there. Anyhow, here's another try:
> 
> Mono can be obtained from:
> http://ftp.novell.com/pub/mono/sources/mono/mono-2.0.1.tar.bz2
> 
> Although 2.0.1 only supports ppc32 the problem is still reproducible.
> 
> Now to the Christmas cheer, i've tried v2.6.28 and couldn't help but
> notice that the problem is gone, bisecting v2.6.27 (which funnily i
> had to mark good) to v2.6.28 (which has to be marked bad) wasn't fun
> but eventually converged at ab598b6680f1e74c267d1547ee352f3e1e530f89
> 
> commit ab598b6680f1e74c267d1547ee352f3e1e530f89
> Author: Paul Mackerras <paulus@samba.org>
> Date:   Sun Nov 30 11:49:45 2008 +0000
> 
>      powerpc: Fix system calls on Cell entered with XER.SO=1
> 
> Now the lock-up is gone, however the code never exercises the path
> taken during the lock-up so i guess it, at least, deserves a better
> look by PPC64 care takers.

I'm confused. Which code never exercises which path, and so what
deserves a better look?

AFAICT this fix will help you, and could explain your problem. You're on
Cell, so you're using the mftb workaround, and ps3_defconfig has
CONFIG_VIRT_CPU_ACCOUNTING=y.

cheers

-- 
Michael Ellerman
OzLabs, IBM Australia Development Lab

wwweb: http://michael.ellerman.id.au
phone: +61 2 6212 1183 (tie line 70 21183)

We do not inherit the earth from our ancestors,
we borrow it from our children. - S.M.A.R.T Person

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Re: Lock-up on PPC64

[Arnd Bergmann]

On Sunday 28 December 2008, malc wrote:
> Now to the Christmas cheer, i've tried v2.6.28 and couldn't help but
> notice that the problem is gone, bisecting v2.6.27 (which funnily i
> had to mark good) to v2.6.28 (which has to be marked bad) wasn't fun
> but eventually converged at ab598b6680f1e74c267d1547ee352f3e1e530f89
>=20
> commit ab598b6680f1e74c267d1547ee352f3e1e530f89
> Author: Paul Mackerras <paulus@samba.org>
> Date: =A0 Sun Nov 30 11:49:45 2008 +0000
>=20
> =A0 =A0 =A0powerpc: Fix system calls on Cell entered with XER.SO=3D1
>=20
> Now the lock-up is gone, however the code never exercises the path
> taken during the lock-up so i guess it, at least, deserves a better
> look by PPC64 care takers.


Yes, this change was suspected to help with Mono as well, not just
Java, because both of them use their own syscall path rather than
going through glibc. The reason why you see the lock-up in a different
place is because the bug manifested in getting incorrect syscall
return codes, which probably made mono go into a normally unused
error handling case.

	Arnd <><

Re: Lock-up on PPC64

[malc]

On Mon, 5 Jan 2009, Michael Ellerman wrote:

> On Sun, 2008-12-28 at 03:45 +0300, malc wrote:
>> On Thu, 25 Dec 2008, Benjamin Herrenschmidt wrote:
>>
>>> On Wed, 2008-12-24 at 03:08 +0300, malc@pulsesoft.com wrote:
>>>> Ken Moffat <zarniwhoop@ntlworld.com> writes:
>>>>
>>>>> On Tue, Dec 23, 2008 at 06:04:45AM +0300, malc@pulsesoft.com wrote:
>>
>> [..snip..]
>>
[..snip..]

>>
>> Now to the Christmas cheer, i've tried v2.6.28 and couldn't help but
>> notice that the problem is gone, bisecting v2.6.27 (which funnily i
>> had to mark good) to v2.6.28 (which has to be marked bad) wasn't fun
>> but eventually converged at ab598b6680f1e74c267d1547ee352f3e1e530f89
>>
>> commit ab598b6680f1e74c267d1547ee352f3e1e530f89
>> Author: Paul Mackerras <paulus@samba.org>
>> Date:   Sun Nov 30 11:49:45 2008 +0000
>>
>>      powerpc: Fix system calls on Cell entered with XER.SO=1
>>
>> Now the lock-up is gone, however the code never exercises the path
>> taken during the lock-up so i guess it, at least, deserves a better
>> look by PPC64 care takers.
>
> I'm confused. Which code never exercises which path, and so what
> deserves a better look?

Before this change (atleast) mono_handle_native_sigsegv was executed
(before machine locks-up hard) after the change this code path is
never touched.

The fact that machine locks up hard and not even magic sysrq works
is what deserves a better look.

[..snip..]

-- 
mailto:av1474@comtv.ru

Re: Lock-up on PPC64

[Benjamin Herrenschmidt]

On Mon, 2009-01-05 at 19:34 +0300, malc wrote:
> Before this change (atleast) mono_handle_native_sigsegv was executed
> (before machine locks-up hard) after the change this code path is
> never touched.
> 
> The fact that machine locks up hard and not even magic sysrq works
> is what deserves a better look.

Indeed. It's possible that the normally not hit error case is triggering
a different bug. Definitely worth looking at.

I didn't have a chance so far, I'm a bit swamped at the moment, but keep
pining me please :-)

Cheers,
Ben.

Re: Lock-up on PPC64

[Benjamin Herrenschmidt]

On Mon, 2009-01-05 at 23:28 +1100, Michael Ellerman wrote:
> I'm confused. Which code never exercises which path, and so what
> deserves a better look?

Well, the thing is with the fix that went into 2.6.30, some error path
will never bit hit, or pretty much.

Without the fix, what can happen is that a syscall incorrectly is
interpreted as returning an error, thus triggering rarely used error
path in Mono. However, that shouldn't lockup the whole machine :-)

So It's still worth investigating what's happening when taking the fix
out, as we may have another bug somewhere lurking.

Cheers,
Ben.

Re: Lock-up on PPC64

[malc]

On Tue, 6 Jan 2009, Benjamin Herrenschmidt wrote:

> On Mon, 2009-01-05 at 19:34 +0300, malc wrote:
>> Before this change (atleast) mono_handle_native_sigsegv was executed
>> (before machine locks-up hard) after the change this code path is
>> never touched.
>>
>> The fact that machine locks up hard and not even magic sysrq works
>> is what deserves a better look.
>
> Indeed. It's possible that the normally not hit error case is triggering
> a different bug. Definitely worth looking at.
>
> I didn't have a chance so far, I'm a bit swamped at the moment, but keep
> pining me please :-)
>

As you wish :) I've written some ad-hoc stuff in the failing path which 
manually triggers sysrq and then sends the klogctl output via network
and here it is:

<6>SysRq : Show State
<6>  task                        PC stack   pid father
<4>init          S 000000000ff23a7c     0     1      0
<4>Call Trace:
<4>[c000000000d87370] [c000000000d87410] 0xc000000000d87410 (unreliable)
<4>[c000000000d87540] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c000000000d875d0] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c000000000d876c0] [c0000000005a3d58] .schedule_timeout+0xa8/0xe8
<4>[c000000000d87790] [c0000000000ed4f4] .do_select+0x410/0x4b0
<4>[c000000000d87b10] [c0000000001182bc] .compat_core_sys_select+0x18c/0x25c
<4>[c000000000d87d00] [c000000000119e60] .compat_sys_select+0xb0/0x190
<4>[c000000000d87dc0] [c000000000014e3c] .ppc32_select+0x14/0x28
<4>[c000000000d87e30] [c000000000008534] syscall_exit+0x0/0x40
<4>kthreadd      S 0000000000000000     0     2      0
<4>Call Trace:
<4>[c000000000d8bbb0] [c000000000d8bc50] 0xc000000000d8bc50 (unreliable)
<4>[c000000000d8bd80] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c000000000d8be10] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c000000000d8bf00] [c0000000000852bc] .kthreadd+0x98/0x1bc
<4>[c000000000d8bf90] [c000000000024d00] .kernel_thread+0x4c/0x68
<4>migration/0   S 0000000000000000     0     3      2
<4>Call Trace:
<4>[c000000007fc7ad0] [c000000007fc7b70] 0xc000000007fc7b70 (unreliable)
<4>[c000000007fc7ca0] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c000000007fc7d30] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c000000007fc7e20] [c000000000067148] .migration_thread+0x228/0x3fc
<4>[c000000007fc7f00] [c000000000085574] .kthread+0x78/0xc4
<4>[c000000007fc7f90] [c000000000024d00] .kernel_thread+0x4c/0x68
<4>ksoftirqd/0   S 0000000000000000     0     4      2
<4>Call Trace:
<4>[c000000007fcbb30] [c000000007fcbbd0] 0xc000000007fcbbd0 (unreliable)
<4>[c000000007fcbd00] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c000000007fcbd90] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c000000007fcbe80] [c000000000071dd8] .ksoftirqd+0x48/0xd4
<4>[c000000007fcbf00] [c000000000085574] .kthread+0x78/0xc4
<4>[c000000007fcbf90] [c000000000024d00] .kernel_thread+0x4c/0x68
<4>watchdog/0    S 0000000000000000     0     5      2
<4>Call Trace:
<4>[c000000007fcfb20] [c000000007fcfbe0] 0xc000000007fcfbe0 (unreliable)
<4>[c000000007fcfcf0] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c000000007fcfd80] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c000000007fcfe70] [c0000000000a1540] .watchdog+0x48/0x70
<4>[c000000007fcff00] [c000000000085574] .kthread+0x78/0xc4
<4>[c000000007fcff90] [c000000000024d00] .kernel_thread+0x4c/0x68
<4>migration/1   S 0000000000000000     0     6      2
<4>Call Trace:
<4>[c000000007fdbad0] [c000000007fdbb70] 0xc000000007fdbb70 (unreliable)
<4>[c000000007fdbca0] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c000000007fdbd30] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c000000007fdbe20] [c000000000067148] .migration_thread+0x228/0x3fc
<4>[c000000007fdbf00] [c000000000085574] .kthread+0x78/0xc4
<4>[c000000007fdbf90] [c000000000024d00] .kernel_thread+0x4c/0x68
<4>ksoftirqd/1   S 0000000000000000     0     7      2
<4>Call Trace:
<4>[c0000000010ebb30] [c0000000010ebbd0] 0xc0000000010ebbd0 (unreliable)
<4>[c0000000010ebd00] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c0000000010ebd90] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c0000000010ebe80] [c000000000071dd8] .ksoftirqd+0x48/0xd4
<4>[c0000000010ebf00] [c000000000085574] .kthread+0x78/0xc4
<4>[c0000000010ebf90] [c000000000024d00] .kernel_thread+0x4c/0x68
<4>watchdog/1    S 0000000000000000     0     8      2
<4>Call Trace:
<4>[c0000000010efb20] [c0000000010efbe0] 0xc0000000010efbe0 (unreliable)
<4>[c0000000010efcf0] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c0000000010efd80] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c0000000010efe70] [c0000000000a1540] .watchdog+0x48/0x70
<4>[c0000000010eff00] [c000000000085574] .kthread+0x78/0xc4
<4>[c0000000010eff90] [c000000000024d00] .kernel_thread+0x4c/0x68
<4>events/0      S 0000000000000000     0     9      2
<4>Call Trace:
<4>[c0000000010fbaf0] [c0000000010fbb90] 0xc0000000010fbb90 (unreliable)
<4>[c0000000010fbcc0] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c0000000010fbd50] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c0000000010fbe40] [c000000000080ea8] .worker_thread+0xa0/0xf0
<4>[c0000000010fbf00] [c000000000085574] .kthread+0x78/0xc4
<4>[c0000000010fbf90] [c000000000024d00] .kernel_thread+0x4c/0x68
<4>events/1      S 0000000000000000     0    10      2
<4>Call Trace:
<4>[c0000000010ffaf0] [c0000000010ffb90] 0xc0000000010ffb90 (unreliable)
<4>[c0000000010ffcc0] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c0000000010ffd50] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c0000000010ffe40] [c000000000080ea8] .worker_thread+0xa0/0xf0
<4>[c0000000010fff00] [c000000000085574] .kthread+0x78/0xc4
<4>[c0000000010fff90] [c000000000024d00] .kernel_thread+0x4c/0x68
<4>khelper       S 0000000000000000     0    11      2
<4>Call Trace:
<4>[c000000000be3af0] [c000000000be3b90] 0xc000000000be3b90 (unreliable)
<4>[c000000000be3cc0] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c000000000be3d50] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c000000000be3e40] [c000000000080ea8] .worker_thread+0xa0/0xf0
<4>[c000000000be3f00] [c000000000085574] .kthread+0x78/0xc4
<4>[c000000000be3f90] [c000000000024d00] .kernel_thread+0x4c/0x68
<4>kblockd/0     S 0000000000000000     0    95      2
<4>Call Trace:
<4>[c0006c005ee2baf0] [c0006c005ee2bb90] 0xc0006c005ee2bb90 (unreliable)
<4>[c0006c005ee2bcc0] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c0006c005ee2bd50] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c0006c005ee2be40] [c000000000080ea8] .worker_thread+0xa0/0xf0
<4>[c0006c005ee2bf00] [c000000000085574] .kthread+0x78/0xc4
<4>[c0006c005ee2bf90] [c000000000024d00] .kernel_thread+0x4c/0x68
<4>kblockd/1     S 0000000000000000     0    96      2
<4>Call Trace:
<4>[c0006c005ee2faf0] [c0006c005ee2fb90] 0xc0006c005ee2fb90 (unreliable)
<4>[c0006c005ee2fcc0] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c0006c005ee2fd50] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c0006c005ee2fe40] [c000000000080ea8] .worker_thread+0xa0/0xf0
<4>[c0006c005ee2ff00] [c000000000085574] .kthread+0x78/0xc4
<4>[c0006c005ee2ff90] [c000000000024d00] .kernel_thread+0x4c/0x68
<4>ata/0         S 0000000000000000     0   104      2
<4>Call Trace:
<4>[c000000007f93af0] [c000000007f93b90] 0xc000000007f93b90 (unreliable)
<4>[c000000007f93cc0] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c000000007f93d50] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c000000007f93e40] [c000000000080ea8] .worker_thread+0xa0/0xf0
<4>[c000000007f93f00] [c000000000085574] .kthread+0x78/0xc4
<4>[c000000007f93f90] [c000000000024d00] .kernel_thread+0x4c/0x68
<4>ata/1         S 0000000000000000     0   105      2
<4>Call Trace:
<4>[c000000007f8baf0] [c000000007f8bb90] 0xc000000007f8bb90 (unreliable)
<4>[c000000007f8bcc0] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c000000007f8bd50] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c000000007f8be40] [c000000000080ea8] .worker_thread+0xa0/0xf0
<4>[c000000007f8bf00] [c000000000085574] .kthread+0x78/0xc4
<4>[c000000007f8bf90] [c000000000024d00] .kernel_thread+0x4c/0x68
<4>ata_aux       S 0000000000000000     0   106      2
<4>Call Trace:
<4>[c0006c005ee5faf0] [c0006c005ee5fb90] 0xc0006c005ee5fb90 (unreliable)
<4>[c0006c005ee5fcc0] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c0006c005ee5fd50] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c0006c005ee5fe40] [c000000000080ea8] .worker_thread+0xa0/0xf0
<4>[c0006c005ee5ff00] [c000000000085574] .kthread+0x78/0xc4
<4>[c0006c005ee5ff90] [c000000000024d00] .kernel_thread+0x4c/0x68
<4>khubd         S 0000000000000000     0   111      2
<4>Call Trace:
<4>[c0006c005ee7ba70] [c0006c005ee7bb10] 0xc0006c005ee7bb10 (unreliable)
<4>[c0006c005ee7bc40] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c0006c005ee7bcd0] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c0006c005ee7bdc0] [c000000000476ef0] .hub_thread+0xc1c/0xcec
<4>[c0006c005ee7bf00] [c000000000085574] .kthread+0x78/0xc4
<4>[c0006c005ee7bf90] [c000000000024d00] .kernel_thread+0x4c/0x68
<4>kseriod       S 0000000000000000     0   114      2
<4>Call Trace:
<4>[c0006c005ee87af0] [c0006c005ee87b90] 0xc0006c005ee87b90 (unreliable)
<4>[c0006c005ee87cc0] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c0006c005ee87d50] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c0006c005ee87e40] [c00000000049da90] .serio_thread+0x33c/0x394
<4>[c0006c005ee87f00] [c000000000085574] .kthread+0x78/0xc4
<4>[c0006c005ee87f90] [c000000000024d00] .kernel_thread+0x4c/0x68
<4>ps3avd        S 0000000000000000     0   145      2
<4>Call Trace:
<4>[c000000000dafaf0] [c000000000dafb90] 0xc000000000dafb90 (unreliable)
<4>[c000000000dafcc0] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c000000000dafd50] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c000000000dafe40] [c000000000080ea8] .worker_thread+0xa0/0xf0
<4>[c000000000daff00] [c000000000085574] .kthread+0x78/0xc4
<4>[c000000000daff90] [c000000000024d00] .kernel_thread+0x4c/0x68
<4>pdflush       S 0000000000000000     0   161      2
<4>Call Trace:
<4>[c00000000108fae0] [c00000000108fb80] 0xc00000000108fb80 (unreliable)
<4>[c00000000108fcb0] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c00000000108fd40] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c00000000108fe30] [c0000000000aebcc] .pdflush+0x124/0x2b8
<4>[c00000000108ff00] [c000000000085574] .kthread+0x78/0xc4
<4>[c00000000108ff90] [c000000000024d00] .kernel_thread+0x4c/0x68
<4>pdflush       S 0000000000000000     0   162      2
<4>Call Trace:
<4>[c0006c005e963ae0] [c0006c005e963b80] 0xc0006c005e963b80 (unreliable)
<4>[c0006c005e963cb0] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c0006c005e963d40] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c0006c005e963e30] [c0000000000aebcc] .pdflush+0x124/0x2b8
<4>[c0006c005e963f00] [c000000000085574] .kthread+0x78/0xc4
<4>[c0006c005e963f90] [c000000000024d00] .kernel_thread+0x4c/0x68
<4>kswapd0       S 0000000000000000     0   163      2
<4>Call Trace:
<4>[c0006c005e967a50] [c0006c005e967af0] 0xc0006c005e967af0 (unreliable)
<4>[c0006c005e967c20] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c0006c005e967cb0] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c0006c005e967da0] [c0000000000b3638] .kswapd+0x10c/0x4b0
<4>[c0006c005e967f00] [c000000000085574] .kthread+0x78/0xc4
<4>[c0006c005e967f90] [c000000000024d00] .kernel_thread+0x4c/0x68
<4>aio/0         S 0000000000000000     0   164      2
<4>Call Trace:
<4>[c0006c005e96baf0] [c0006c005e96bb90] 0xc0006c005e96bb90 (unreliable)
<4>[c0006c005e96bcc0] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c0006c005e96bd50] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c0006c005e96be40] [c000000000080ea8] .worker_thread+0xa0/0xf0
<4>[c0006c005e96bf00] [c000000000085574] .kthread+0x78/0xc4
<4>[c0006c005e96bf90] [c000000000024d00] .kernel_thread+0x4c/0x68
<4>aio/1         S 0000000000000000     0   165      2
<4>Call Trace:
<4>[c0006c005e96faf0] [c0006c005e96fb90] 0xc0006c005e96fb90 (unreliable)
<4>[c0006c005e96fcc0] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c0006c005e96fd50] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c0006c005e96fe40] [c000000000080ea8] .worker_thread+0xa0/0xf0
<4>[c0006c005e96ff00] [c000000000085574] .kthread+0x78/0xc4
<4>[c0006c005e96ff90] [c000000000024d00] .kernel_thread+0x4c/0x68
<4>ps3fb         S 0000000000000000     0   173      2
<4>Call Trace:
<4>[c000000000dfbb30] [c000000000dfbbd0] 0xc000000000dfbbd0 (unreliable)
<4>[c000000000dfbd00] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c000000000dfbd90] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c000000000dfbe80] [c00000000026e228] .ps3fbd+0x44/0x70
<4>[c000000000dfbf00] [c000000000085574] .kthread+0x78/0xc4
<4>[c000000000dfbf90] [c000000000024d00] .kernel_thread+0x4c/0x68
<4>khvcd         S 0000000000000000     0   757      2
<4>Call Trace:
<4>[c000000000ee3b20] [c000000000ee3bc0] 0xc000000000ee3bc0 (unreliable)
<4>[c000000000ee3cf0] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c000000000ee3d80] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c000000000ee3e70] [c00000000028faa8] .khvcd+0x100/0x170
<4>[c000000000ee3f00] [c000000000085574] .kthread+0x78/0xc4
<4>[c000000000ee3f90] [c000000000024d00] .kernel_thread+0x4c/0x68
<4>khvcsd        S 0000000000000000     0   832      2
<4>Call Trace:
<4>[c000000000eb7af0] [c000000000eb7b90] 0xc000000000eb7b90 (unreliable)
<4>[c000000000eb7cc0] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c000000000eb7d50] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c000000000eb7e40] [c0000000002914e4] .khvcsd+0x260/0x2b0
<4>[c000000000eb7f00] [c000000000085574] .kthread+0x78/0xc4
<4>[c000000000eb7f90] [c000000000024d00] .kernel_thread+0x4c/0x68
<4>scsi_eh_0     S 0000000000000000     0   916      2
<4>Call Trace:
<4>[c000000000fd7ad0] [c000000000fd7b70] 0xc000000000fd7b70 (unreliable)
<4>[c000000000fd7ca0] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c000000000fd7d30] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c000000000fd7e20] [c0000000002f8dc0] .scsi_error_handler+0x5c/0x374
<4>[c000000000fd7f00] [c000000000085574] .kthread+0x78/0xc4
<4>[c000000000fd7f90] [c000000000024d00] .kernel_thread+0x4c/0x68
<4>rpciod/0      S 0000000000000000     0  1001      2
<4>Call Trace:
<4>[c0006c005ea8faf0] [c0006c005ea8fb90] 0xc0006c005ea8fb90 (unreliable)
<4>[c0006c005ea8fcc0] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c0006c005ea8fd50] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c0006c005ea8fe40] [c000000000080ea8] .worker_thread+0xa0/0xf0
<4>[c0006c005ea8ff00] [c000000000085574] .kthread+0x78/0xc4
<4>[c0006c005ea8ff90] [c000000000024d00] .kernel_thread+0x4c/0x68
<4>rpciod/1      S 0000000000000000     0  1002      2
<4>Call Trace:
<4>[c000000000dabaf0] [c000000000dabb90] 0xc000000000dabb90 (unreliable)
<4>[c000000000dabcc0] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c000000000dabd50] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c000000000dabe40] [c000000000080ea8] .worker_thread+0xa0/0xf0
<4>[c000000000dabf00] [c000000000085574] .kthread+0x78/0xc4
<4>[c000000000dabf90] [c000000000024d00] .kernel_thread+0x4c/0x68
<4>kjournald     S 0000000000000000     0  1009      2
<4>Call Trace:
<4>[c0006c005b8bfad0] [c0006c005b8bfb70] 0xc0006c005b8bfb70 (unreliable)
<4>[c0006c005b8bfca0] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c0006c005b8bfd30] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c0006c005b8bfe20] [c00000000015ffc8] .kjournald+0x1d0/0x29c
<4>[c0006c005b8bff00] [c000000000085574] .kthread+0x78/0xc4
<4>[c0006c005b8bff90] [c000000000024d00] .kernel_thread+0x4c/0x68
<4>kauditd       S 0000000000000000     0  1041      2
<4>Call Trace:
<4>[c0006c005a00fae0] [c0006c005a00fb80] 0xc0006c005a00fb80 (unreliable)
<4>[c0006c005a00fcb0] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c0006c005a00fd40] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c0006c005a00fe30] [c00000000009adc0] .kauditd_thread+0x14c/0x1a4
<4>[c0006c005a00ff00] [c000000000085574] .kthread+0x78/0xc4
<4>[c0006c005a00ff90] [c000000000024d00] .kernel_thread+0x4c/0x68
<4>udevd         S 000000001feb2a7c     0  1075      1
<4>Call Trace:
<4>[c0006c005eed7370] [c0006c005eed7410] 0xc0006c005eed7410 (unreliable)
<4>[c0006c005eed7540] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c0006c005eed75d0] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c0006c005eed76c0] [c0000000005a3cec] .schedule_timeout+0x3c/0xe8
<4>[c0006c005eed7790] [c0000000000ed4f4] .do_select+0x410/0x4b0
<4>[c0006c005eed7b10] [c0000000001182bc] .compat_core_sys_select+0x18c/0x25c
<4>[c0006c005eed7d00] [c000000000119e80] .compat_sys_select+0xd0/0x190
<4>[c0006c005eed7dc0] [c000000000014e3c] .ppc32_select+0x14/0x28
<4>[c0006c005eed7e30] [c000000000008534] syscall_exit+0x0/0x40
<4>kjournald     S 0000000000000000     0  2644      2
<4>Call Trace:
<4>[c0006c005902fad0] [c0006c005902fb70] 0xc0006c005902fb70 (unreliable)
<4>[c0006c005902fca0] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c0006c005902fd30] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c0006c005902fe20] [c00000000015ffc8] .kjournald+0x1d0/0x29c
<4>[c0006c005902ff00] [c000000000085574] .kthread+0x78/0xc4
<4>[c0006c005902ff90] [c000000000024d00] .kernel_thread+0x4c/0x68
<4>spusched      S 0000000000000000     0  2650      2
<4>Call Trace:
<4>[c0006c00590d3b10] [c0006c00590d3bb0] 0xc0006c00590d3bb0 (unreliable)
<4>[c0006c00590d3ce0] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c0006c00590d3d70] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c0006c00590d3e60] [d00000000016a99c] .spusched_thread+0x40/0x10c [spufs]
<4>[c0006c00590d3f00] [c000000000085574] .kthread+0x78/0xc4
<4>[c0006c00590d3f90] [c000000000024d00] .kernel_thread+0x4c/0x68
<4>syslogd       S 000000001ff68be0     0  3030      1
<4>Call Trace:
<4>[c0006c005928b410] [c0006c005928b4b0] 0xc0006c005928b4b0 (unreliable)
<4>[c0006c005928b5e0] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c0006c005928b670] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c0006c005928b760] [c0000000005a3cec] .schedule_timeout+0x3c/0xe8
<4>[c0006c005928b830] [c0000000004e8d04] .skb_recv_datagram+0x1e4/0x2b8
<4>[c0006c005928b910] [c000000000568470] .unix_dgram_recvmsg+0x88/0x2a8
<4>[c0006c005928ba00] [c0000000004dd968] .sock_recvmsg+0xd0/0x110
<4>[c0006c005928bc00] [c0000000004dee94] .sys_recvfrom+0xec/0x170
<4>[c0006c005928bd90] [c0000000004fea4c] .compat_sys_socketcall+0x178/0x214
<4>[c0006c005928be30] [c000000000008534] syscall_exit+0x0/0x40
<4>klogd         R  running task        0  3033      1
<4>irqbalance    S 000000001ff25918     0  3050      1
<4>Call Trace:
<4>[c0006c005931f970] [c0006c005931fa10] 0xc0006c005931fa10 (unreliable)
<4>[c0006c005931fb40] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c0006c005931fbd0] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c0006c005931fcc0] [c0000000005a3d58] .schedule_timeout+0xa8/0xe8
<4>[c0006c005931fd90] [c000000000096bb8] .compat_sys_nanosleep+0x90/0x128
<4>[c0006c005931fe30] [c000000000008534] syscall_exit+0x0/0x40
<4>portmap       S 000000001ff194e0     0  3073      1
<4>Call Trace:
<4>[c0006c0059407550] [c0006c00594075f0] 0xc0006c00594075f0 (unreliable)
<4>[c0006c0059407720] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c0006c00594077b0] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c0006c00594078a0] [c0000000005a3d58] .schedule_timeout+0xa8/0xe8
<4>[c0006c0059407970] [c0000000000ecf38] .do_sys_poll+0x2c8/0x410
<4>[c0006c0059407d90] [c0000000000ed0cc] .sys_poll+0x4c/0x64
<4>[c0006c0059407e30] [c000000000008534] syscall_exit+0x0/0x40
<4>rpc.idmapd    S 000000001feab6b4     0  3102      1
<4>Call Trace:
<4>[c0006c00595e7910] [c0006c00595e79b0] 0xc0006c00595e79b0 (unreliable)
<4>[c0006c00595e7ae0] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c0006c00595e7b70] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c0006c00595e7c60] [c0000000005a3d58] .schedule_timeout+0xa8/0xe8
<4>[c0006c00595e7d30] [c0000000001157a4] .sys_epoll_wait+0x188/0x530
<4>[c0006c00595e7e30] [c000000000008534] syscall_exit+0x0/0x40
<4>lockd         S 0000000000000000     0  3141      2
<4>Call Trace:
<4>[c0006c00593ef9b0] [c0006c00593efa50] 0xc0006c00593efa50 (unreliable)
<4>[c0006c00593efb80] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c0006c00593efc10] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c0006c00593efd00] [c0000000005a3cec] .schedule_timeout+0x3c/0xe8
<4>[c0006c00593efdd0] [c000000000583c80] .svc_recv+0x314/0x534
<4>[c0006c00593efec0] [c0000000001c67f0] .lockd+0x14c/0x2a8
<4>[c0006c00593eff90] [c000000000024d00] .kernel_thread+0x4c/0x68
<4>sshd          S 000000001fa2ba7c     0  3193      1
<4>Call Trace:
<4>[c0006c005992f370] [c0006c005992f410] 0xc0006c005992f410 (unreliable)
<4>[c0006c005992f540] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c0006c005992f5d0] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c0006c005992f6c0] [c0000000005a3cec] .schedule_timeout+0x3c/0xe8
<4>[c0006c005992f790] [c0000000000ed4f4] .do_select+0x410/0x4b0
<4>[c0006c005992fb10] [c0000000001182bc] .compat_core_sys_select+0x18c/0x25c
<4>[c0006c005992fd00] [c000000000119e80] .compat_sys_select+0xd0/0x190
<4>[c0006c005992fdc0] [c000000000014e3c] .ppc32_select+0x14/0x28
<4>[c0006c005992fe30] [c000000000008534] syscall_exit+0x0/0x40
<4>mingetty      S 000000000ff1a6d4     0  3216      1
<4>Call Trace:
<4>[c0006c00597ef700] [c0006c00597ef7a0] 0xc0006c00597ef7a0 (unreliable)
<4>[c0006c00597ef8d0] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c0006c00597ef960] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c0006c00597efa50] [c0000000005a3cec] .schedule_timeout+0x3c/0xe8
<4>[c0006c00597efb20] [c00000000027afe0] .read_chan+0x3bc/0x770
<4>[c0006c00597efc30] [c000000000276bb4] .tty_read+0xc0/0x14c
<4>[c0006c00597efcf0] [c0000000000dbcf8] .vfs_read+0xd8/0x1a4
<4>[c0006c00597efd90] [c0000000000dc3f4] .sys_read+0x4c/0x8c
<4>[c0006c00597efe30] [c000000000008534] syscall_exit+0x0/0x40
<4>mingetty      S 000000000ff1a6d4     0  3218      1
<4>Call Trace:
<4>[c0006c00591df700] [c0006c00591df7a0] 0xc0006c00591df7a0 (unreliable)
<4>[c0006c00591df8d0] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c0006c00591df960] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c0006c00591dfa50] [c0000000005a3cec] .schedule_timeout+0x3c/0xe8
<4>[c0006c00591dfb20] [c00000000027afe0] .read_chan+0x3bc/0x770
<4>[c0006c00591dfc30] [c000000000276bb4] .tty_read+0xc0/0x14c
<4>[c0006c00591dfcf0] [c0000000000dbcf8] .vfs_read+0xd8/0x1a4
<4>[c0006c00591dfd90] [c0000000000dc3f4] .sys_read+0x4c/0x8c
<4>[c0006c00591dfe30] [c000000000008534] syscall_exit+0x0/0x40
<4>mingetty      S 000000000ff1a6d4     0  3219      1
<4>Call Trace:
<4>[c0006c005981b700] [c0006c005981b7a0] 0xc0006c005981b7a0 (unreliable)
<4>[c0006c005981b8d0] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c0006c005981b960] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c0006c005981ba50] [c0000000005a3cec] .schedule_timeout+0x3c/0xe8
<4>[c0006c005981bb20] [c00000000027afe0] .read_chan+0x3bc/0x770
<4>[c0006c005981bc30] [c000000000276bb4] .tty_read+0xc0/0x14c
<4>[c0006c005981bcf0] [c0000000000dbcf8] .vfs_read+0xd8/0x1a4
<4>[c0006c005981bd90] [c0000000000dc3f4] .sys_read+0x4c/0x8c
<4>[c0006c005981be30] [c000000000008534] syscall_exit+0x0/0x40
<4>mingetty      S 000000000ff1a6d4     0  3221      1
<4>Call Trace:
<4>[c0006c00598af700] [c0006c00598af7a0] 0xc0006c00598af7a0 (unreliable)
<4>[c0006c00598af8d0] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c0006c00598af960] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c0006c00598afa50] [c0000000005a3cec] .schedule_timeout+0x3c/0xe8
<4>[c0006c00598afb20] [c00000000027afe0] .read_chan+0x3bc/0x770
<4>[c0006c00598afc30] [c000000000276bb4] .tty_read+0xc0/0x14c
<4>[c0006c00598afcf0] [c0000000000dbcf8] .vfs_read+0xd8/0x1a4
<4>[c0006c00598afd90] [c0000000000dc3f4] .sys_read+0x4c/0x8c
<4>[c0006c00598afe30] [c000000000008534] syscall_exit+0x0/0x40
<4>mingetty      S 000000000ff1a6d4     0  3222      1
<4>Call Trace:
<4>[c0006c005985b700] [c0006c005985b7a0] 0xc0006c005985b7a0 (unreliable)
<4>[c0006c005985b8d0] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c0006c005985b960] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c0006c005985ba50] [c0000000005a3cec] .schedule_timeout+0x3c/0xe8
<4>[c0006c005985bb20] [c00000000027afe0] .read_chan+0x3bc/0x770
<4>[c0006c005985bc30] [c000000000276bb4] .tty_read+0xc0/0x14c
<4>[c0006c005985bcf0] [c0000000000dbcf8] .vfs_read+0xd8/0x1a4
<4>[c0006c005985bd90] [c0000000000dc3f4] .sys_read+0x4c/0x8c
<4>[c0006c005985be30] [c000000000008534] syscall_exit+0x0/0x40
<4>mingetty      S 000000000ff1a6d4     0  3224      1
<4>Call Trace:
<4>[c0006c00597e3700] [c0006c00597e37a0] 0xc0006c00597e37a0 (unreliable)
<4>[c0006c00597e38d0] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c0006c00597e3960] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c0006c00597e3a50] [c0000000005a3cec] .schedule_timeout+0x3c/0xe8
<4>[c0006c00597e3b20] [c00000000027afe0] .read_chan+0x3bc/0x770
<4>[c0006c00597e3c30] [c000000000276bb4] .tty_read+0xc0/0x14c
<4>[c0006c00597e3cf0] [c0000000000dbcf8] .vfs_read+0xd8/0x1a4
<4>[c0006c00597e3d90] [c0000000000dc3f4] .sys_read+0x4c/0x8c
<4>[c0006c00597e3e30] [c000000000008534] syscall_exit+0x0/0x40
<4>sshd          S 000000001fa226d4     0  3279   3193
<4>Call Trace:
<4>[c0006c0059a034e0] [c0006c0059a03580] 0xc0006c0059a03580 (unreliable)
<4>[c0006c0059a036b0] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c0006c0059a03740] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c0006c0059a03830] [c0000000005a3cec] .schedule_timeout+0x3c/0xe8
<4>[c0006c0059a03900] [c000000000567abc] .unix_stream_recvmsg+0x2a4/0x650
<4>[c0006c0059a03a40] [c0000000004dcdc8] .sock_aio_read+0x104/0x12c
<4>[c0006c0059a03b50] [c0000000000db480] .do_sync_read+0xc4/0x124
<4>[c0006c0059a03cf0] [c0000000000dbd14] .vfs_read+0xf4/0x1a4
<4>[c0006c0059a03d90] [c0000000000dc3f4] .sys_read+0x4c/0x8c
<4>[c0006c0059a03e30] [c000000000008534] syscall_exit+0x0/0x40
<4>sshd          R  running task        0  3281   3279
<4>bash          S 000000000ff1a6d4     0  3282   3281
<4>Call Trace:
<4>[c0006c00599e3700] [c0006c00599e37a0] 0xc0006c00599e37a0 (unreliable)
<4>[c0006c00599e38d0] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c0006c00599e3960] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c0006c00599e3a50] [c0000000005a3cec] .schedule_timeout+0x3c/0xe8
<4>[c0006c00599e3b20] [c00000000027afe0] .read_chan+0x3bc/0x770
<4>[c0006c00599e3c30] [c000000000276bb4] .tty_read+0xc0/0x14c
<4>[c0006c00599e3cf0] [c0000000000dbcf8] .vfs_read+0xd8/0x1a4
<4>[c0006c00599e3d90] [c0000000000dc3f4] .sys_read+0x4c/0x8c
<4>[c0006c00599e3e30] [c000000000008534] syscall_exit+0x0/0x40
<4>sshd          S 000000001fa226d4     0  3323   3193
<4>Call Trace:
<4>[c0006c0059f834e0] [c0006c0059f83580] 0xc0006c0059f83580 (unreliable)
<4>[c0006c0059f836b0] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c0006c0059f83740] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c0006c0059f83830] [c0000000005a3cec] .schedule_timeout+0x3c/0xe8
<4>[c0006c0059f83900] [c000000000567abc] .unix_stream_recvmsg+0x2a4/0x650
<4>[c0006c0059f83a40] [c0000000004dcdc8] .sock_aio_read+0x104/0x12c
<4>[c0006c0059f83b50] [c0000000000db480] .do_sync_read+0xc4/0x124
<4>[c0006c0059f83cf0] [c0000000000dbd14] .vfs_read+0xf4/0x1a4
<4>[c0006c0059f83d90] [c0000000000dc3f4] .sys_read+0x4c/0x8c
<4>[c0006c0059f83e30] [c000000000008534] syscall_exit+0x0/0x40
<4>sshd          S 000000001fa2ba7c     0  3325   3323
<4>Call Trace:
<4>[c0006c0059f93370] [c0006c0059f93410] 0xc0006c0059f93410 (unreliable)
<4>[c0006c0059f93540] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c0006c0059f935d0] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c0006c0059f936c0] [c0000000005a3cec] .schedule_timeout+0x3c/0xe8
<4>[c0006c0059f93790] [c0000000000ed4f4] .do_select+0x410/0x4b0
<4>[c0006c0059f93b10] [c0000000001182bc] .compat_core_sys_select+0x18c/0x25c
<4>[c0006c0059f93d00] [c000000000119e80] .compat_sys_select+0xd0/0x190
<4>[c0006c0059f93dc0] [c000000000014e3c] .ppc32_select+0x14/0x28
<4>[c0006c0059f93e30] [c000000000008534] syscall_exit+0x0/0x40
<4>bash          S 000000000fee9118     0  3326   3325
<4>Call Trace:
<4>[c0006c0059f73930] [c0006c0059f739d0] 0xc0006c0059f739d0 (unreliable)
<4>[c0006c0059f73b00] [c00000000000e8d8] .__switch_to+0x110/0x144
<4>[c0006c0059f73b90] [c0000000005a2e68] .schedule+0x5a8/0x728
<4>[c0006c0059f73c80] [c00000000006efb8] .do_wait+0xe4c/0x1070
<4>[c0006c0059f73dc0] [c000000000014548] .compat_sys_waitpid+0x18/0x2c
<4>[c0006c0059f73e30] [c000000000008534] syscall_exit+0x0/0x40
<4>dlog          R  running task        0  3363   3326
<4>Sched Debug Version: v0.05-v20, 2.6.23-9.ydl6.1 #1
<4>now at 90061762394 nsecs
<4>
<4>cpu#0
<4>  .nr_running                    : 3
<4>  .load                          : 5169
<4>  .ls.delta_fair                 : 41806983440
<4>  .ls.delta_exec                 : 89976330074
<4>  .nr_switches                   : 31519
<4>  .nr_load_updates               : 22494
<4>  .nr_uninterruptible            : 197
<4>  .jiffies                       : 4294914790
<4>  .next_balance                  : 4294914815
<4>  .curr->pid                     : 3050
<4>  .clock                         : 89976330074
<4>  .idle_clock                    : 0
<4>  .prev_clock_raw                : 89976330336
<4>  .clock_warps                   : 0
<4>  .clock_overflows               : 16260
<4>  .clock_deep_idle_events        : 0
<4>  .clock_max_delta               : 4000000
<4>  .cpu_load[0]                   : 1024
<4>  .cpu_load[1]                   : 1024
<4>  .cpu_load[2]                   : 1024
<4>  .cpu_load[3]                   : 1024
<4>  .cpu_load[4]                   : 1024
<4>
<4>cfs_rq
<4>  .fair_clock                    : 9850601511
<4>  .exec_clock                    : 17038500532
<4>  .wait_runtime                  : 0
<4>  .wait_runtime_overruns         : 0
<4>  .wait_runtime_underruns        : 0
<4>  .sleeper_bonus                 : 1535299
<4>  .wait_runtime_rq_sum           : 59697736
<4>
<4>runnable tasks:
<4>            task   PID        tree-key         delta       waiting  switches  prio        sum-exec        sum-wait       sum-sleep    wait-overrun   wait-underrun
<4>------------------------------------------------------------------------------------------------------------------------------------------------------------------
<4>           ps3fb   173      9837477513     -13123998      40000000      5311   115               0               0               0               0               0
<4>R     irqbalance  3050      9810447679     -40153832      39849424         6   120               0               0               0               0               0
<4>            sshd  3281      9870579167      19977656     -20151688       280   120               0               0               0               0               0
<4>
<4>cpu#1
<4>  .nr_running                    : 3
<4>  .load                          : 5169
<4>  .ls.delta_fair                 : 42447067418
<4>  .ls.delta_exec                 : 90004018170
<4>  .nr_switches                   : 18967
<4>  .nr_load_updates               : 22503
<4>  .nr_uninterruptible            : -197
<4>  .jiffies                       : 4294914790
<4>  .next_balance                  : 4294914822
<4>  .curr->pid                     : 3363
<4>  .clock                         : 90016005724
<4>  .idle_clock                    : 0
<4>  .prev_clock_raw                : 90116240256
<4>  .clock_warps                   : 0
<4>  .clock_overflows               : 16229
<4>  .clock_deep_idle_events        : 0
<4>  .clock_max_delta               : 4000000
<4>  .cpu_load[0]                   : 5169
<4>  .cpu_load[1]                   : 4973
<4>  .cpu_load[2]                   : 4179
<4>  .cpu_load[3]                   : 3335
<4>  .cpu_load[4]                   : 2896
<4>
<4>cfs_rq
<4>  .fair_clock                    : 7132545922
<4>  .exec_clock                    : 14197356548
<4>  .wait_runtime                  : 0
<4>  .wait_runtime_overruns         : 0
<4>  .wait_runtime_underruns        : 0
<4>  .sleeper_bonus                 : 3144905
<4>  .wait_runtime_rq_sum           : 38151694
<4>
<4>runnable tasks:
<4>            task   PID        tree-key         delta       waiting  switches  prio        sum-exec        sum-wait       sum-sleep    wait-overrun   wait-underrun
<4>------------------------------------------------------------------------------------------------------------------------------------------------------------------
<4>        events/1    10      7115462305     -18668451      40000000       582   115               0               0               0               0               0
<4>           klogd  3033      6698428379    -435702377      38151694       433   120               0               0               0               0               0
<4>R           dlog  3363      7174130756      40000000     -40000000         9   120               0               0               0               0               0
<4>

-- 
mailto:av1474@comtv.ru

Re: Lock-up on PPC64

[Benjamin Herrenschmidt]

> As you wish :) I've written some ad-hoc stuff in the failing path which 
> manually triggers sysrq and then sends the klogctl output via network
> and here it is:

Allright, something's unclear to me. What do you mean by the system goes
down then ? The kernel appears to be working at least to a certain
extent if you manage to trigger a sysrq from userspace... And from what
I see, it looks that all processes are somewhere in schedule.

So what is precisely your symptom here ?

Cheers,
Ben.

Re: Lock-up on PPC64

[malc]

On Wed, 7 Jan 2009, Benjamin Herrenschmidt wrote:

>
>> As you wish :) I've written some ad-hoc stuff in the failing path which
>> manually triggers sysrq and then sends the klogctl output via network
>> and here it is:
>
> Allright, something's unclear to me. What do you mean by the system goes
> down then ? The kernel appears to be working at least to a certain
> extent if you manage to trigger a sysrq from userspace... And from what
> I see, it looks that all processes are somewhere in schedule.
>
> So what is precisely your symptom here ?

Okay full setup is like this:

1. Default ydl kernel (2.6.23) (i.e. without XER.SO patch)

2. Mono with mono_handle_native_sigsegv augmented with code
    that write(2)s a byte to an file which corresponds to a FIFO

3. Small application that is blocking on the read side of the FIFO and
    upon receiving anything, write(2)s "t\nd\n" to /proc/sysrq-trigger,
    then grabs the printk buffer via klogctl and send(2)s it.

Given all that, I have two connections to PS3 - one is running the
dlog (application described in item 3), and the other is used to run
Mono with arguments that lead to the lock up.

After Mono is invoked one can see that mono_handle_native_sigsegv is
executed (few debugging write(2)s) and also that local copy of nc,
which dlog connects to, has received printk buffer, PS3 meanwhile
locks up.

Hope it's clearer now, if not, please, do ask.

-- 
mailto:av1474@comtv.ru

Re: Lock-up on PPC64

[malc]

On Wed, 7 Jan 2009, malc wrote:

> On Wed, 7 Jan 2009, Benjamin Herrenschmidt wrote:
> 
> > 
> > > As you wish :) I've written some ad-hoc stuff in the failing path which
> > > manually triggers sysrq and then sends the klogctl output via network
> > > and here it is:
> > 
> > Allright, something's unclear to me. What do you mean by the system goes
> > down then ? The kernel appears to be working at least to a certain
> > extent if you manage to trigger a sysrq from userspace... And from what
> > I see, it looks that all processes are somewhere in schedule.
> > 
> > So what is precisely your symptom here ?

After writing valgrind tool that was simulating Cell XER.SO syscall
(mis)behaviour (pre ab598b6680f1e74c267d1547ee352f3e1e530f89 that is)
and banging my had against the wall for a while trying to figure out
which of the failing syscalls was responsible, i've tried to be simple
and after only ~30 minutes came up with this, rather short, piece of
code that knocks pre XER.SO patched kernels out cold:

gcc -o xer -x assembler /dev/stdin -nostdlib <<eof
.globl _start
_start:
         addis 0,0,0x8000
         mtxer 0
         addi 0,0,1
         sc
eof

-- 
mailto:av1474@comtv.ru

Re: Lock-up on PPC64

[Benjamin Herrenschmidt]

On Sun, 2009-02-22 at 11:35 +0300, malc wrote:
> After writing valgrind tool that was simulating Cell XER.SO syscall
> (mis)behaviour (pre ab598b6680f1e74c267d1547ee352f3e1e530f89 that is)
> and banging my had against the wall for a while trying to figure out
> which of the failing syscalls was responsible, i've tried to be simple
> and after only ~30 minutes came up with this, rather short, piece of
> code that knocks pre XER.SO patched kernels out cold:
> 
> gcc -o xer -x assembler /dev/stdin -nostdlib <<eof
> .globl _start
> _start:
>          addis 0,0,0x8000
>          mtxer 0
>          addi 0,0,1
>          sc

Allright, but the XER patch fixes it... interesting. Oh well, I'll try
to figure out at some stage where we get something wrong in those old
kernels.

Cheers,
Ben.

Re: Lock-up on PPC64

[Geoff Levand]

On 01/05/2009 07:46 AM, Arnd Bergmann wrote:
> On Sunday 28 December 2008, malc wrote:
>> Now to the Christmas cheer, i've tried v2.6.28 and couldn't help but
>> notice that the problem is gone, bisecting v2.6.27 (which funnily i
>> had to mark good) to v2.6.28 (which has to be marked bad) wasn't fun
>> but eventually converged at ab598b6680f1e74c267d1547ee352f3e1e530f89
>> 
>> commit ab598b6680f1e74c267d1547ee352f3e1e530f89
>> Author: Paul Mackerras <paulus@samba.org>
>> Date:   Sun Nov 30 11:49:45 2008 +0000
>> 
>>      powerpc: Fix system calls on Cell entered with XER.SO=1
>> 
>> Now the lock-up is gone, however the code never exercises the path
>> taken during the lock-up so i guess it, at least, deserves a better
>> look by PPC64 care takers.
> 
> 
> Yes, this change was suspected to help with Mono as well, not just
> Java, because both of them use their own syscall path rather than
> going through glibc. The reason why you see the lock-up in a different
> place is because the bug manifested in getting incorrect syscall
> return codes, which probably made mono go into a normally unused
> error handling case.

Just FYI, I looked into a problem of Mono that was reported during
its build.  During the build Mono itself is used, and it failed due
to lack of memory.  Mono kept using more and more memory until all
was consumed.  I didn't look at why, I just saw it with the Gnome
system monitor.

-Geoff