Keep getting segmentation fault and malloc error for reading stdin - c

Question

I tried to run a C program that reads from stdin and stores them in char**, but I keep getting either malloc: Incorrect checksum for freed object or segmentation fault errors whenever realloc is used to increase the size of the pointer. Can anyone point out what I did wrong? The program is example 7_14 from beginning C 5th ed. Below is the code I ran without using C11 optional string functions because my clang complier doesn't seem to support them.
// Program 7.14 Using array notation with pointers to sort strings
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#define BUF_LEN 100
#define COUNT 5
int main(void)
{
char buf[BUF_LEN]; // Input buffer
size_t str_count = 0; // Current string count
size_t capacity = COUNT; // Current maximum number of strings
char **pS = calloc(capacity, sizeof(char *)); // Pointers to strings
char **psTemp = NULL; // Temporary pointer to pointer to char
char *pTemp = NULL; // Temporary pointer to char
size_t str_len = 0; // Length of a string
bool sorted = false; // Indicated when strings are sorted
printf("Enter strings to be sorted, one per line. Press Enter to end:\n");
// Read in all the strings
char *ptr = NULL;
while (*fgets(buf, BUF_LEN, stdin) != '\n')
{
if(str_count == capacity)
{
capacity += capacity/4;
if (!(psTemp = realloc(pS, capacity))) return 1;
pS = psTemp;
}
str_len = strnlen(buf, BUF_LEN) + 1;
if (!(pS[str_count] = malloc(str_len))) return 2;
strcpy(pS[str_count++], buf);
}
// Sort the strings in ascending order
while(!sorted)
{
sorted = true;
for(size_t i = 0; i < str_count - 1; ++i)
{
if(strcmp(pS[i], pS[i + 1]) > 0)
{
sorted = false;
pTemp = pS[i];
pS[i] = pS[i+1];
pS[i+1] = pTemp;
}
}
}
// Output the sorted strings
printf("Your input sorted in ascending sequence is:\n\n");
for(size_t i = 0; i < str_count; ++i)
{
printf("%s", pS[i]);
free(pS[i]);
pS[i] = NULL;
}
free(pS);
pS = NULL;
return 0;
}
Example execution result:
Enter strings to be sorted, one per line. Press Enter to end:
Many a mickle makes a muckle.
A fool and your money are soon partners.
Every dog has his day.
Do unto others before they do it to you.
A nod is as good as a wink to a blind horse.
The bigger they are, the harder they hit.
[1] 82729 segmentation fault ./7_14