[Crash-utility] How does crash find booted kernel?

[Buland Kumar Singh]

On 2 November 2015 at 09:09, Nan Xiao <xiaonan830818 at gmail.com> wrote:

> Hi all,
>
> I am trying to use crash on RHEL 7.0.After executing "crash" command,
> it outputs:
>
>     crash: cannot find booted kernel -- please enter namelist argument
>
> After referring to crash white paper
> (https://people.redhat.com/anderson/crash_whitepaper/),
> I know it needs vmlinux file. So I install "kernel-debuginfo" package:
>
> [root at localhost boot]# rpm -ql kernel-debuginfo | grep vmlinux
> /usr/lib/debug/lib/modules/3.10.0-123.el7.x86_64/vmlinux
>
> Then execute crash, it still prompts the same error:
>
>     crash: cannot find booted kernel -- please enter namelist argument
>
> I try to copy vmlinux file into /boot directory, but this error still
> exists.
>
> How can I fix this issue? Thanks very much in advance!
>
> Best Regards
> Nan Xiao
>
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> Crash-utility at redhat.com
> https://www.redhat.com/mailman/listinfo/crash-utility
>


Hi Nan,

You need to make sure that the version of kernel-debuginfo package must
match with the version of running kernel.

Eg:
# rpm -q kernel
kernel-3.10.0-229.el7.x86_64

# uname -r
3.10.0-229.el7.x86_64

# rpm -q kernel-debuginfo
package kernel-debuginfo is not installed

# rpm -ivh kernel-debuginfo-common-x86_64-3.10.0-229.el7.x86_64.rpm
Preparing...                          #################################
[100%]
Updating / installing...
   1:kernel-debuginfo-common-x86_64-3.#################################
[100%]

# rpm -ivh kernel-debuginfo-3.10.0-229.el7.x86_64.rpm
Preparing...                          #################################
[100%]
Updating / installing...
   1:kernel-debuginfo-3.10.0-229.el7  #################################
[100%]

# rpm -q kernel-debuginfo
kernel-debuginfo-3.10.0-229.el7.x86_64

# crash -s

crash> sys
      KERNEL: /usr/lib/debug/lib/modules/3.10.0-229.el7.x86_64/vmlinux
    DUMPFILE: /dev/crash
        CPUS: 2
        DATE: Mon Nov  2 12:41:58 2015
      UPTIME: 00:13:18
LOAD AVERAGE: 0.37, 0.37, 0.18
       TASKS: 122
    NODENAME: localhost.localdomain
     RELEASE: 3.10.0-229.el7.x86_64
     VERSION: #1 SMP Thu Jan 29 18:37:38 EST 2015
     MACHINE: x86_64  (2790 Mhz)
      MEMORY: 2 GB

-- 
BKS
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