pipe causing processes to freeze

The program report launches two accessed processes. Report basically feeds accessed a list of filenames and accessed prints if they have been accessed in x days.

However, my implementation is causing accessed to freeze somehow. After running reports, nothing gets printed. When I run ps, I can see two accessed programs hanging around, not dying.

At first, I thought the method of reading from stdin was wrong in accessed, but I manually piped some filenames to it cat filenames.txt | ./accessed, and it works. So report program must be wrong.

Relevant parts of report:

if (!(pid_A1 = fork())) {
            char *num_arg = NULL;
            size_t arg_sz = 16;
            num_arg = (char *) malloc(arg_sz * sizeof(char));
            snprintf(num_arg, arg_sz, "%d", cmd_args->num);

            close(pipe_RtoA1[1]);
            dup2(pipe_RtoA1[0], 0);
            close(pipe_RtoA1[0]);

            execl("accessed", "accessed", num_arg, (char *)0);
    } else if (!(pid_A2 = fork())) {
            char *num_arg = NULL;
            size_t arg_sz = 16;
            num_arg = (char *) malloc(arg_sz * sizeof(char));
            snprintf(num_arg, arg_sz, "%d", -(cmd_args->num));

            close(pipe_RtoA2[1]);
            dup2(pipe_RtoA2[0], 0);
            close(pipe_RtoA2[0]);

            execl("accessed", "accessed", num_arg, (char *) 0);
     } else {
            FILE *fRtoA1 = NULL;
            FILE *fRtoA2 = NULL;
            fRtoA1 = fdopen(pipe_RtoA1[1], "w");
            fRtoA2 = fdopen(pipe_RtoA2[1], "w");
            close(pipe_RtoA1[0]);
            close(pipe_RtoA2[0]);
            fprintf(fRtoA1, "%s", file_paths);
            fprintf(fRtoA2, "%s", file_paths);
    }

Relevant parts of accessed:

char **process_input() 
{
        char **file_paths = NULL;
        char *input_str = NULL;
        size_t len = 0;
        size_t file_paths_sz = 10;
        unsigned int fcnt = 0;
        long read = 0;
        char delim[] = " ";

        if ((file_paths = (char **) malloc(file_paths_sz * sizeof(char *))) == NULL) {
                exit_program("malloc for file_paths failed.");
        }

        while((read = getline(&input_str, &len, stdin)) != EOF) { //FREEZES HERE
                char *tmp_string = NULL;
                strip_token(input_str);

                tmp_string = strtok(input_str, delim);
                *(file_paths + fcnt) = (char *) malloc(sizeof(char) * (strlen(tmp_string) + 1));
                strncpy(*(file_paths + fcnt), tmp_string, strlen(tmp_string) + 1);
                strip_token(*(file_paths + fcnt));
                fcnt++;

                while ((tmp_string = strtok(NULL, delim))) {
                        *(file_paths + fcnt) = (char *) malloc(sizeof(char) * (strlen(tmp_string) + 1));
                        strncpy(*(file_paths + fcnt), tmp_string, strlen(tmp_string) + 1);
                        strip_token(*(file_paths + fcnt));
                        if ((fcnt + 1) == file_paths_sz) {
                                file_paths_sz *= 2;
                                file_paths = realloc(file_paths, file_paths_sz * sizeof(char *));
                        }
                        fcnt++;
                }
        }

        return file_paths;
}

I attached gdb to the frozen accessed processes and it seems that it is frozen at the while loop getline. So I changed the while loop to a single getline statement and it suddenly works. However, I need to read stdin until EOF. Any help on the possible sources of errors is very much appreciated. This is causing me much headache.