Re: [BUG] i386 2.6.18 cpu_up: attempt to bring up CPU 4 failed :kernel BUG at mm/slab.c:2698!

[keith mannthey]

On Thu, 2006-09-21 at 21:09 -0700, David Rientjes wrote: 
> On Thu, 21 Sep 2006, Andrew Morton wrote:

Well I think there is 3 bug total exposed my unique situation. I think
all 3 issues are generic mainline bugs that have been around for
awhile.   

1. SRAT not being mapped (patch submitted to fix boot_ioremap code)
  This caused cpus to fail to be borough on line and panicked the box. 

2.  The panic is bad.  I have so far tested the patch David
submitted....  It allowed the cpu_up calls to fail without panicking the
box.  Andrew do you want me to test yours or ???

3. Flat mode i386 numa on a real numa system is broken.  If there is
only 1 node in the system cpus should think they are apart of some other
node.     Patch below.  



  If cases where a real numa system boots the Flat numa option make sure
the cpus don't claim to be apart on a non-existent node.


Signed-off-by: Keith Mannthey <kmannth@xxxxxxxxxx>

--- linux-2.6.18/arch/i386/kernel/smpboot.c	2006-09-19
20:42:06.000000000 -0700
+++ linux-2.6.18-workes/arch/i386/kernel/smpboot.c	2006-09-21
21:57:55.000000000 -0700
@@ -642,9 +642,13 @@
 {
 	int cpu = smp_processor_id();
 	int apicid = logical_smp_processor_id();
-
+	int node = apicid_to_node(apicid);
+	
+	if (!node_online(node))
+		node = first_online_node;
+	
 	cpu_2_logical_apicid[cpu] = apicid;
-	map_cpu_to_node(cpu, apicid_to_node(apicid));
+	map_cpu_to_node(cpu, node);
 }
 
 static void unmap_cpu_to_logical_apicid(int cpu)


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