Subject: PASEMI: PA6T board doesn't boot with the RC1 of kernel 4.2 anymore

From: Christian Zigotzky <[email-masked]>
Date: Wed, 8 Jul 2015 20:00:31 +0200

Dear Linuxppc-dev mailing list,

I used git bisect and found out that the following commit is the problem.

commit 3ceaccdf92073d193f0bfbe24280dd736e3fed86
Author: Dave Hansen <[email-masked]>

Log:

git clone 
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git linux-git

git bisect start b953c0d234bc72e8489d3bf51a276c5c4ec85345 (Linux 4.1)

git bisect bad d770e558e21961ad6cfdf0ff7df0eb5d7d4f0754 (Linux 4.2-rc1)

Output:

Bisecting: 6261 revisions left to test after this (roughly 13 steps)
[4570a37169d4b44d316f40b2ccc681dc93fedc7b] Merge tag 'sound-4.2-rc1' of 
git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound

----

git bisect bad

Output:

Bisecting: 3295 revisions left to test after this (roughly 12 steps)
[4e241557fc1cb560bd9e77ca1b4a9352732a5427] Merge tag 'for-linus' of 
git://git.kernel.org/pub/scm/virt/kvm/kvm

----

git bisect bad

Output:

Bisecting: 1625 revisions left to test after this (roughly 11 steps)
[44d21c3f3a2ef2f58b18bda64c52c99e723f3f4a] Merge 
git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6

----

git bisect bad

Output:

Bisecting: 712 revisions left to test after this (roughly 10 steps)
[e75c73ad64478c12b3a44b86a3e7f62a4f65b93e] Merge branch 
'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

----

git bisect bad (sometimes the kernel boots but the mouse doesn't work)

Output:

Bisecting: 371 revisions left to test after this (roughly 9 steps)
[c58267e9fa7b0345dd9006939254701e3622ca6a] Merge branch 
'perf-core-for-linus' of 
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

----

git bisect good

Output:

Bisecting: 185 revisions left to test after this (roughly 8 steps)
[59a36d16be8f9f68410f1bd396577fb7f31ae877] x86/fpu: Factor out 
fpu/regset.h from fpu/internal.h

----

git bisect good

Output:

Bisecting: 93 revisions left to test after this (roughly 7 steps)
[23b7776290b10297fe2cae0fb5f166a4f2c68121] Merge branch 
'sched-core-for-linus' of 
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

----

git bisect good

Output:

Bisecting: 46 revisions left to test after this (roughly 6 steps)
[0c4109bec0a6cde471bef3a21cd6f8384a614469] x86/fpu/xstate: Fix up bad 
get_xsave_addr() assumptions

----

git bisect good

Output:

Bisecting: 19 revisions left to test after this (roughly 5 steps)
[cfe3eceb7a2eb91284d5605c5315249bb165e9d3] Merge branch 
'x86-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

----

git bisect good

Output:

Bisecting: 9 revisions left to test after this (roughly 3 steps)
[cd4996dce18b619bd7b3acf75c91f49c77f05a97] x86/mpx: Trace allocation of 
new bounds tables

----

git bisect good

Output:

Bisecting: 4 revisions left to test after this (roughly 2 steps)
[613fcb7d3c79ec25b5913a6aa974c9047c31e68c] x86/mpx: Support 32-bit 
binaries on 64-bit kernels

----

git bisect good

Output:

Bisecting: 2 revisions left to test after this (roughly 1 step)
[bea03c50b871a2fa922f31ad7c9993bb4fc7b192] x86/mpx: Do not count MPX 
VMAs as neighbors when unmapping

----

git bisect bad (sometimes the kernel boots but the mouse doesn't work)

Output:

Bisecting: 0 revisions left to test after this (roughly 0 steps)
[3ceaccdf92073d193f0bfbe24280dd736e3fed86] x86/mpx: Rewrite the unmap code

----

git bisect bad (sometimes the kernel boots but the mouse doesn't work)

Output:

3ceaccdf92073d193f0bfbe24280dd736e3fed86 is the first bad commit
commit 3ceaccdf92073d193f0bfbe24280dd736e3fed86
Author: Dave Hansen <[email-masked]>
Date:   Sun Jun 7 11:37:06 2015 -0700

     x86/mpx: Rewrite the unmap code

     The MPX code needs to clear out bounds tables for memory which
     is no longer in use.  We do this when a userspace mapping is
     torn down (unmapped).

     There are two modes:

       1. An entire bounds table becomes unused, and can be freed
          and its pointer removed from the bounds directory.  This
          happens either when a large mapping is torn down, or when
          a small mapping is torn down and it is the last mapping
          "covered" by a bounds table.

       2. Only part of a bounds table becomes unused, in which case
          we free the backing memory as if MADV_DONTNEED was called.

     The old code was a spaghetti mess of "edge" bounds tables
     where the edges were handled specially, even if we were
     unmapping an entire one.  Non-edge bounds tables are always
     fully unmapped, but share a different code path from the edge
     ones.  The old code had a bug where it was unmapping too much
     memory.  I worked on fixing it for two days and gave up.

     I didn't write the original code.  I didn't particularly like
     it, but it worked, so I left it.  After my debug session, I
     realized it was undebuggagle *and* buggy, so out it went.

     I also wrote a new unmapping test program which uncovers bugs
     pretty nicely.

     Signed-off-by: Dave Hansen <[email-masked]>
     Reviewed-by: Thomas Gleixner <[email-masked]>
     Cc: Andrew Morton <[email-masked]>
     Cc: Dave Hansen <[email-masked]>
     Cc: H. Peter Anvin <[email-masked]>
     Cc: Linus Torvalds <[email-masked]>
     Cc: Peter Zijlstra <[email-masked]>
     Link: 
http://lkml.kernel.org/r/[email-masked]
     Signed-off-by: Ingo Molnar <[email-masked]>

:040000 040000 d6809ce6030ff42a5813da4a94971888d8ad67c9 
a0514265bbf313aba996e5606c00881acc62b220 M    arch

----

Cheers,

Christian

On 07 July 2015 2:44 PM, Christian Zigotzky wrote:
>
>
> Error messages images:
>
> http://forum.hyperion-entertainment.biz/download/file.php?id=1772&mode=view 
>
> http://forum.hyperion-entertainment.biz/download/file.php?id=1774&mode=view 
>
>
> -- Christian
>
> On 07 July 2015 12:50 PM Christian Zigotzky wrote:
>> Dear Linuxppc-dev mailing list,
>>
>> I compiled a kernel from the git on Tuesday 23rd of June 2015. It
>> didn't boot with my PASEMI PA6T board.
>>
>> Error messages:
>>
>> Oops: Kernel access of bad area, sig: 11 [#1]
>>
>> .sb600_8259_cascade+0x4c/0xac (unreliable)
>> .schedule+0x74/0x9c (unreliable)
>>
>> Kernel panic - not syncing: Fatal exception in interrupt
>>
>> I compiled the RC1 of kernel 4.2 last Sunday. Unfortunately it didn't
>> boot either. The kernel 4.1 and 4.1.1 boot without any problems.
>>
>> Could someone please explain me why it doesn't boot anymore?
>>
>> I would like to thank you very much in advance for helping me.
>>
>> If you have any questions, please don't hesitate to ask. I'm looking
>> forward to getting your reply.
>>
>>
>> Kind regards,
>>
>> Christian Zigotzky
>>
>>
>> _______________________________________________
>> Linuxppc-dev mailing list
>> [email-masked]
>> https://lists.ozlabs.org/listinfo/linuxppc-dev
>
>
>
> _______________________________________________
> Linuxppc-dev mailing list
> [email-masked]
> https://lists.ozlabs.org/listinfo/linuxppc-dev