Segmentation fault: Cannot access memory at address

This is my code:

Code:

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#include <stdio.h>
#include <limits.h>
#include <stdlib.h>

int parse_string (const char *s1, char *s2) {
        int pos = 0;
        while ( (*s1 != '\0') || (*s1 != '\t') ) {
                *s2 = *s1;
                s2++;
                s1++;
                pos++;
        }
        *s2 = '\0';
        return pos;
}

int main() {
        FILE *ptr;
        int index;
        printf ("We're going to read the first five entries in pkg-config:\n");
        ptr = popen ("pkg-config --list-all", "r");
        char line[LINE_MAX];
        index = 0;
        while ( (index <= 5) && (fgets(line, LINE_MAX, ptr) != NULL) ) {
                char *tmp = malloc (LINE_MAX);
                parse_string (line, tmp);
                printf ("%s", tmp);
                free (tmp);
                index++;
        }
        fclose (ptr);
        return 0;
}

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I'm trying to read the first entries and remove the tab character, but it gives me Segmentation fault, any ideas?

Code:

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while ( (*s1 != '\0') || (*s1 != '\t') )

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You have the wrong logic here. When will this ever be false? (Hint: it won't.)

You should also check the return value of "malloc()" to make sure it successfully allocated memory before trying to use that memory.

Also, don't forget to check that popen() succeeded before you use ptr. If ptr is NULL, print a useful error message (e.g. via perror) and exit.