Re: 3.11-rc2: panic in __rdmsr_on_cpu

From: Srinivas Pandruvada
Date: Fri Jul 26 2013 - 10:54:07 EST


This is already fixed and it is in Linus main line. Check commit id "f3ed0a17f0292300b3caca32d823ecd32554a667"


Thanks for analysis and you are correct.

Thanks,
Srinivas

On 07/26/2013 06:15 AM, Ilia Mirkin wrote:
On Fri, Jul 26, 2013 at 7:59 AM, Ilia Mirkin <imirkin@xxxxxxxxxxxx> wrote:
On Thu, Jul 25, 2013 at 6:32 PM, Ilia Mirkin <imirkin@xxxxxxxxxxxx> wrote:
Hi,

I just built a 3.11-rc2 kernel (+ a few patches, but nothing
arch-related), and I saw the following: http://i.imgur.com/dCTqOyR.jpg

The rough transcription is

Call Trace:
<IRQ>
generic_smp_call_fucntion_single_interrupt
smp_call_function_single_interrupt
call_function_single_interrupt
<EOI>
? default_idle
? default_idle
arch_cpu_idle
cpu_startup_entry
rest_init
start_kernel
? repair_env_string
x86_64_start_reservations
x86_64_start_kernel
Code: ... cc 81 8b 0f <0f> 32 48 c1 e2 20 89 c0 ...
RIP: __rdmsr_on_cpu+0x2e/0x44
Kernel panic - not syncing: Fatal exception in interrupt

A 3.10-rc7 kernel booted just fine. Is this likely a real issue? Or
perhaps a mis-build of some sort?
FWIW this is repeatable. I did a clean build (make clean && make) and
I still see the same thing. I have a Core i7-920 cpu, not sure what
other information would be relevant. I'd love to avoid a bisect, so
some likely candidates would be most welcome.
Aha, figured it out. I had enabled "X86 package temperature thermal
driver" = Y, which caused my Core i7-920 to produce the above trace on
boot. Glancing over the code, should this:

if (!cpu_has(c, X86_FEATURE_DTHERM) &&
!cpu_has(c, X86_FEATURE_PTS))
return -ENODEV;

perhaps be

if (!cpu_has(c, X86_FEATURE_DTHERM) ||
!cpu_has(c, X86_FEATURE_PTS))
return -ENODEV;

i.e. are both of those things required, or just one of them? My cpu
has DTHERM but not PTS, according to /proc/cpuinfo.

-ilia


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