How can I fix this error in C using valgrind: invalid write of size 8

After compiling my code, I've got some issues regarding the memory. After doing ./valgrind on my Linux terminal, I've got the following error for this function:

> invalid write of size 8 at read_lines_from_file.

Here is my function read_lines_from_file:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <math.h>

int lines_count = 0;
char** read_lines_from_file(FILE* file) {
    fseek(file, 0, SEEK_SET);
    char** lines = NULL;// ça renvoie NULL si le fichier est vide
    char  line[100];
    while (fgets(line, 100, file)) {// nous faisons l'hypothèse qu'une ligne ne dépasse pas 100 caractères
        line[strlen(line)-1]='
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <math.h>
int lines_count = 0;
char** read_lines_from_file(FILE* file) {
fseek(file, 0, SEEK_SET);
char** lines = NULL;// ça renvoie NULL si le fichier est vide
char  line[100];
while (fgets(line, 100, file)) {// nous faisons l'hypothèse qu'une ligne ne dépasse pas 100 caractères
line[strlen(line)-1]='\0';// on enlève le \n
lines = realloc(lines, (lines_count + 1) * sizeof(char*));
lines[lines_count] = malloc(strlen(line) + 1);
strcpy(lines[lines_count], line);
lines_count++;
}
return lines;
}
';// on enlève le \n
        lines = realloc(lines, (lines_count + 1) * sizeof(char*));
        lines[lines_count] = malloc(strlen(line) + 1);
        strcpy(lines[lines_count], line);
        lines_count++;
    }
    return lines;
}

I don't understand where it comes from and how I can correct that to remove this error.

Code has at least these problems:

Unclear if any solve "invalid write of size 1 at split".

Caller lacks info as to how many lines were read

read_lines_from_file, on the 2nd call is not reset to 0 and so conveys to the caller the wrong number of lines.

Hacker exploit

line[strlen(line)-1]='\0'; is UB where the first character read is a null character.

Also, input does not certainly include a '\n'.

 // Better as
line[strcspn(line, "\n")] = '
 // Better as
line[strcspn(line, "\n")] = '\0';
';

Lack of error checking

Code does not check for allocation errors.

Lines of 100+ characters are not well handled