This is a note to let you know that I've just added the patch titled
x86, amd: Fix panic on AMD CPU family 0x15
to the 2.6.36-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
x86-amd-fix-panic-on-amd-cpu-family-0x15.patch
and it can be found in the queue-2.6.36 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From [email protected] Mon Dec 20 15:36:51 2010
From: Andreas Herrmann <[email protected]>
Date: Thu, 16 Dec 2010 21:29:37 +0100
Subject: x86, amd: Fix panic on AMD CPU family 0x15
To: "[email protected]" <[email protected]>
Message-ID: <[email protected]>
Content-Disposition: inline
From: Andreas Herrmann <[email protected]>
[The mainline kernel doesn't have this problem. Commit "(23588c3) x86,
amd: Add support for CPUID topology extension of AMD CPUs" removed the
family check. But 2.6.32.y needs to be fixed.]
This CPU family check is not required -- existence of the NodeId MSR
is indicated by a CPUID feature flag which is already checked in
amd_fixup_dcm() -- and it needlessly prevents amd_fixup_dcm() to be
called for newer AMD CPUs.
In worst case this can lead to a panic in the scheduler code for AMD
family 0x15 multi-node AMD CPUs. I just have a picture of VGA console
output so I can't copy-and-paste it herein, but the call stack of such
a panic looked like:
do_divide_error
...
find_busiest_group
run_rebalance_domains
...
apic_timer_interrupt
...
cpu_idle
The mainline kernel doesn't have this problem. Commit "(23588c3) x86,
amd: Add support for CPUID topology extension of AMD CPUs" removed the
family check. But 2.6.32.y needs to be fixed.
Signed-off-by: Andreas Herrmann <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/kernel/cpu/amd.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -305,8 +305,7 @@ static void __cpuinit amd_detect_cmp(str
/* use socket ID also for last level cache */
per_cpu(cpu_llc_id, cpu) = c->phys_proc_id;
/* fixup topology information on multi-node processors */
- if ((c->x86 == 0x10) && (c->x86_model == 9))
- amd_fixup_dcm(c);
+ amd_fixup_dcm(c);
#endif
}
Patches currently in stable-queue which might be from [email protected]
are
queue-2.6.36/x86-amd-fix-panic-on-amd-cpu-family-0x15.patch
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