Bug#529312: linux-image-2.6.26-2-686-bigmem: Does not recognize all CPUs on summit SMP machines

2009-05-25 Thread Andreas U. Trottmann 
On Mon, May 18, 2009 at 05:04:53PM -0600, dann frazier wrote:

 A fix has been committed. It would be helpful if you could test a
 lenny snaphot build and confirm the fix. Information on installing
 snapshots is available here:
 
   http://wiki.debian.org/DebianKernel
 
 The version you will want to test will be = 2.6.26-16~snapshot.13633
 and should be available after the next daily build cycle.

Thank you very much for your extremely fast response.

I've checked the wiki page and the repository it references.
Also, I've checked the directory with the debs:

http://kernel-archive.buildserver.net/debian-kernel/pool/main/l/linux-2.6/


Unfortunately, it appears the latest i386 lenny kernel snapshot
is snapshot.13538 - all more recent ones are either not lenny
or not i386. I'll continue to check and will report any success
as soon as there will be a suitable kernel (lenny, i386, =
2.6.26-16~snapshot.13633) to test.


With kind regards,

-- 
Andreas Trottmann



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Bug#529312: linux-image-2.6.26-2-686-bigmem: Does not recognize all CPUs on summit SMP machines

2009-05-18 Thread Andreas U. Trottmann 
Package: linux-image-2.6.26-2-686-bigmem
Version: 2.6.26-15

Hello,

The Linux kernel sources upon which
linux-image-2.6.26-2-686-bigmem is based are suffering from a
bug, which only affects the (relatively rare) summit SMP
architecture. It is found in IBM xSeries servers such as the 
x440 or x445.

On these servers, linux-image-2.6.26-2-686-bigmem only correctly
identifies and uses one CPU, regardless of the number of CPUs 
actually installed.

The bug is documented and resolved on linux-kernel:

http://lkml.indiana.edu/hypermail/linux/kernel/0807.3/0493.html

The patch responsible for the resolution is the following:

--- a/include/asm-x86/mach-summit/mach_apic.h 2008-07-24 18:06:39.0 
-0700
+++ b/include/asm-x86/mach-summit/mach_apic.h 2008-07-24 18:09:29.0 
-0700
@@ -122,7 +122,7 @@ static inline physid_mask_t ioapic_phys_

 static inline physid_mask_t apicid_to_cpu_present(int apicid)
 {
- return physid_mask_of_physid(0);
+ return physid_mask_of_physid(apicid);
 }


I report the bug against a lenny kernel, as I don't have any such system 
running 
testing or unstable. The current linux kernel source in unstable, 
linux-2.6_2.6.29-5,
appears to have the file structure reorganized. The relevant file appears to be
arch/x86/include/asm/summit/apic.h, and the bug appears still to be present: 
apicid_to_cpu_present still returns physid_mask_of_physid(0) instead of 
(apicid).

However, currently I cannot test whether the fix is still relevant.

If it is of help, I could try to boot an unpatched linux-2.6_2.6.29-5 kernel on 
a 
summit machine and compare the number of identified CPUs with a patched 
linux-2.6_2.6.29-5
kernel.

In any case, it could probably be a good idea to include the fix in the next 
lenny 
kernel update, as it does render those multi-CPU machines relatively useless, 
and
the fix does not affect anyone else.



With kind regards,

-- 
Andreas Trottmann



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Bug#529312: linux-image-2.6.26-2-686-bigmem: Does not recognize all CPUs on summit SMP machines

2009-05-18 Thread dann frazier 
On Mon, May 18, 2009 at 05:11:41PM +0200, Andreas U. Trottmann wrote:
 Package: linux-image-2.6.26-2-686-bigmem
 Version: 2.6.26-15
 
 Hello,
 
 The Linux kernel sources upon which
 linux-image-2.6.26-2-686-bigmem is based are suffering from a
 bug, which only affects the (relatively rare) summit SMP
 architecture. It is found in IBM xSeries servers such as the 
 x440 or x445.
 
 On these servers, linux-image-2.6.26-2-686-bigmem only correctly
 identifies and uses one CPU, regardless of the number of CPUs 
 actually installed.
 
 The bug is documented and resolved on linux-kernel:
 
 http://lkml.indiana.edu/hypermail/linux/kernel/0807.3/0493.html
 
 The patch responsible for the resolution is the following:
 
 --- a/include/asm-x86/mach-summit/mach_apic.h 2008-07-24 18:06:39.0 
 -0700
 +++ b/include/asm-x86/mach-summit/mach_apic.h 2008-07-24 18:09:29.0 
 -0700
 @@ -122,7 +122,7 @@ static inline physid_mask_t ioapic_phys_
 
  static inline physid_mask_t apicid_to_cpu_present(int apicid)
  {
 - return physid_mask_of_physid(0);
 + return physid_mask_of_physid(apicid);
  }
 
 
 I report the bug against a lenny kernel, as I don't have any such system 
 running 
 testing or unstable. The current linux kernel source in unstable, 
 linux-2.6_2.6.29-5,
 appears to have the file structure reorganized. The relevant file appears to 
 be
 arch/x86/include/asm/summit/apic.h, and the bug appears still to be present: 
 apicid_to_cpu_present still returns physid_mask_of_physid(0) instead of 
 (apicid).
 
 However, currently I cannot test whether the fix is still relevant.
 
 If it is of help, I could try to boot an unpatched linux-2.6_2.6.29-5 kernel 
 on a 
 summit machine and compare the number of identified CPUs with a patched 
 linux-2.6_2.6.29-5
 kernel.

A fix has been committed. It would be helpful if you could test a
lenny snaphot build and confirm the fix. Information on installing
snapshots is available here:

  http://wiki.debian.org/DebianKernel

The version you will want to test will be = 2.6.26-16~snapshot.13633
and should be available after the next daily build cycle.

 In any case, it could probably be a good idea to include the fix in the next 
 lenny 
 kernel update, as it does render those multi-CPU machines relatively useless, 
 and
 the fix does not affect anyone else.
 
 
 
 With kind regards,
 

-- 
dann frazier




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