[Crash-utility] nr_cpus is not calculated properly

[Wei Jiang]

Hi,

I found nr_cpus is not calculated properly in 32 bits(x86) at
crash-4.0-8.9.

Around line 140 in file lkcd_v8.c.
   137           * to find out how many CPUs are configured.
   138           */
   139          offset = offsetof(dump_header_asm_t, dha_smp_regs[0]);
   140          nr_cpus = (hdr_size - offset) /   sizeof(dump_CPU_info_t);
   141
   142          fprintf(stderr, "CPU number NR_CPUS %d \n", NR_CPUS);
   143          fprintf(stderr, "header_asm_t size %d \n",
   sizeof(dump_header_asm_t));
 
And in the corresponding head file.
# cat -n lkcd_dump_v8.h|grep -A 20 434
   434          /* smp specific */
   435          uint32_t        dha_smp_num_cpus;
   436          uint32_t        dha_dumping_cpu;
   437          struct pt_regs  dha_smp_regs[NR_CPUS];
   438          uint32_t        dha_smp_current_task[NR_CPUS];
   439          uint32_t        dha_stack[NR_CPUS];
   440          uint32_t        dha_stack_ptr[NR_CPUS];
   441  } __attribute__((packed)) dump_header_asm_t;
   442
   443  /*
   444   * CPU specific part of dump_header_asm_t
   445   */
   446  typedef struct dump_CPU_info_s {
   447          struct pt_regs  dha_smp_regs;
   448          uint64_t        dha_smp_current_task;
   449          uint64_t        dha_stack;
   450          uint64_t        dha_stack_ptr;
   451  } __attribute__ ((packed)) dump_CPU_info_t;
   452
   453
   454  /*

As we know, on x86(32 bits), uint32_t is 4 bytes and uint64_t is 8
bytes. 

So this line
   140          nr_cpus = (hdr_size - offset) /   sizeof(dump_CPU_info_t);

would not get a correct nr_cpus due to the sizeof().

A patch to fix this problem as below.

Thanks.
-Wj

--- lkcd_dump_v8.h.orig 2009-04-16 13:14:22.000000000 -0400
+++ lkcd_dump_v8.h      2009-06-10 03:31:37.815122032 -0400
@@ -445,9 +445,9 @@ typedef struct _dump_header_asm_s {
  */
 typedef struct dump_CPU_info_s {
        struct pt_regs  dha_smp_regs;
-       uint64_t        dha_smp_current_task;
-       uint64_t        dha_stack;
-       uint64_t        dha_stack_ptr;
+       uint32_t        dha_smp_current_task;
+       uint32_t        dha_stack;
+       uint32_t        dha_stack_ptr;
 } __attribute__ ((packed)) dump_CPU_info_t;