Re: [PATCH] x86, cpuinfo fix cpu_data(0) x86_model_id field truncation

[Borislav Petkov <bp@alien8.de>]

On Mon, May 18, 2015 at 02:21:00PM -0400, Prarit Bhargava wrote:
> When comparing 'model name' fields in /proc/cpuinfo it was noticed that
> a simple test comparing the model name fields was failing.  After some
> simple investigation it was noticed that, in fact, the model name fields
> are different for each processor.  Processor 0's model name field had
> white space removed, while the other processors did not.
> 
> Another way of seeing this behaviour is to convert spaces into underscores
> in the output of /proc/cpuinfo,
> 
> [thetango@prarit ~]# grep "^model name" /proc/cpuinfo | uniq -c | sed 's/\ /_/g'
> ______1_model_name      :_AMD_Opteron(TM)_Processor_6272
> _____63_model_name      :_AMD_Opteron(TM)_Processor_6272_________________
> 
> which shows two different model name fields even though they should be the
> same.
> 
> This occurs because the kernel calls strim() on cpu 0's x86_model_id field

I'd actually prefer this much simpler patch:

---
diff --git a/arch/x86/kernel/cpu/proc.c b/arch/x86/kernel/cpu/proc.c
index e7d8c7608471..d215e9b26567 100644
--- a/arch/x86/kernel/cpu/proc.c
+++ b/arch/x86/kernel/cpu/proc.c
@@ -67,7 +67,7 @@ static int show_cpuinfo(struct seq_file *m, void *v)
 		   c->x86_vendor_id[0] ? c->x86_vendor_id : "unknown",
 		   c->x86,
 		   c->x86_model,
-		   c->x86_model_id[0] ? c->x86_model_id : "unknown");
+		   c->x86_model_id[0] ? strim(c->x86_model_id) : "unknown");
 
 	if (c->x86_mask || c->cpuid_level >= 0)
 		seq_printf(m, "stepping\t: %d\n", c->x86_mask);
---

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
--