Re: [Crash-utility] [PATCH] Support cpu_map/cpu_mask changes in 2.6.29

Wednesday, 29 April 2009

----- "Michael Holzheu" <holzheu(a)linux.vnet.ibm.com&gt; wrote:

...
 Hi Dave,

 I tested my patch and it worked. But it only worked by chance. I read
 the address using readmem(cpu_mask_size) in combination with ULONG(),
 which is nonsense.
 
 So the correct (and tested) version would be something like:
 
 static ulong
 get_cpu_map_addr_from_mask(const char *type)
 {
         char cpu_mask_symbol[32];
         ulong cpu_map_addr;
 
         sprintf(cpu_mask_symbol, "cpu_%s_mask", type);
 
         if (!symbol_exists(cpu_mask_symbol))
                 return 0;
 
         get_symbol_data(cpu_mask_symbol, sizeof(ulong), &cpu_map_addr);
         return cpu_map_addr;
 } 
OK good -- I'll probably just fold the above into cpu_map_addr().

Also, this change, although it doesn't break things, doesn't make
sense because this instance of "cpu_online_map" is a symbol in the
xen hypervisor binary, i.e., not the one in the vmlinux code:

--- crash-4.0-8.9.orig/xen_hyper.c
+++ crash-4.0-8.9/xen_hyper.c
@@ -1815,7 +1815,7 @@ xen_hyper_get_cpu_info(void)
                error(FATAL, "cannot malloc cpumask space.\n");
        }
        /* kakuma: It may be better to use cpu_present_map. */
-       addr = symbol_value("cpu_online_map");
+       addr = cpu_map_addr("online");
        if (!readmem(addr, KVADDR, xht->cpumask,
                XEN_HYPER_SIZE(cpumask_t), "cpu_online_map", RETURN_ON_ERROR))
{
                error(FATAL, "cannot read cpu_online_map.\n");

Thanks,
  Dave


    

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