Linux – Unable to Create a Core File for a Crashed Program

coredumpfilegdblinux

I am using Ubuntu 12.04 LTS. I wrote a simple program as follows to create crash

// null.c
#include<stdio.h>

int main()
{
   int *p = NULL;
   int k=*p;
   printf("%d",sizeof(0));
   return 0;
}

Now I run with "gcc -g null.c"
and then "./a.out" and the output is as expected.

Segmentation fault (core dumped)

Now I want to see the core dump file using gdb. I did the following things

  1. I checked the current directory, there is no core dump file
  2. I tried tried to change the /proc/sys/kernel/core_pattern with the content "core.%e.%p". But i am not able to write into the file. It is saying "Fsync Failed".
  3. I used the "sudo vi /proc/sys/kernel/core_pattern". Still can't write into the file.

I want to create the core dump in my current directory. What to do now?

Best Answer

Your real question appears to be not "where is my core dump", but rather "how can I modify /proc/sys/kernel/core_pattern".

sudo bash -c 'echo core.%e.%p > /proc/sys/kernel/core_pattern'

should do the trick.

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