无法在崩溃实用程序中加载我的模块符号

Question

我在使用centos7上的崩溃调试vmcore时遇到问题。我无法加载模块符号。

sudo crash ../vmlinux-3.10.0-123.el7.x86_64 vmcore
      KERNEL: ../vmlinux-3.10.0-123.el7.x86_64  
    DUMPFILE: vmcore  [PARTIAL DUMP]
        CPUS: 1
        DATE: Tue Aug 18 14:53:54 2015
      UPTIME: 20:33:05
LOAD AVERAGE: 2.39, 1.21, 0.61
       TASKS: 340
    NODENAME: localhost.localdomain
     RELEASE: 3.10.0-123.el7.x86_64
     VERSION: #1 SMP Mon Jun 30 12:09:22 UTC 2014
     MACHINE: x86_64  (3092 Mhz)
      MEMORY: 1.2 GB
       PANIC: "Oops: 0002 [#1] SMP " (check log for details)
         PID: 8327
     COMMAND: "cat"
        TASK: ffff8800279a6660  [THREAD_INFO: ffff880002ade000]
         CPU: 0
       STATE: TASK_RUNNING (PANIC)

    crash> mod -s ext4
         MODULE       NAME                 SIZE  OBJECT FILE
    ffffffffa016f320  ext4               528957  /lib/modules/3.10.0-123.el7.x86_64/kernel/fs/ext4/ext4.ko 

    crash> ls
           ioctal-drv.ko  vmcore  vmcore-dmesg.txt

    crash> mod -s ./ioctal-drv.ko
    Usage:
      mod -s module [objfile] | -d module | -S [directory] [-D|-t|-r|-R|-o|-g]
    Enter "help mod" for details.
    crash> mod -s ioctal-drv.ko
    Usage:
      mod -s module [objfile] | -d module | -S [directory] [-D|-t|-r|-R|-o|-g]
    Enter "help mod" for details.

$ ls -a /sys/module/ioctal_drv/sections/

.  ..  .bss  .data  .gnu.linkonce.this_module  __mcount_loc  .note.gnu.build-id  .rodata  .rodata.str1.1  .rodata.str1.8  .strtab  .symtab  .text

有人可以告诉我为什么我无法加载模块符号吗？感谢