C - realloc causes crash - c

Question

I'm trying to implement a dynamyc array of strings (which can be any length) read from console. However it crashes on the realloc() call in the loop. The code:
void kill(char **memory, int count) {
if (memory != NULL) {
for (int i = 0; i < count; i++) {
if (memory[i] != NULL) {
free(memory[i]);
}
}
free(memory);
}
}
char **getData(int *strCount, int *allocatedCount) {
int maxStrCount = 10;
int maxStrLength = 10;
char **data = malloc(sizeof(char *) * maxStrCount);
if (data == NULL) {
return NULL;
}
for (int i = 0; i < maxStrCount; i++) {
data[i] = malloc(sizeof(char) * maxStrLength);
if (data[i] == NULL) {
kill(data, i);
return NULL;
}
}
int i = 0;
int j = 0;
for (char ch = getchar(); ch != EOF; ch = getchar()) {
if (ch == '\n') { // if end of line
data[i][j] = '\0';
i++;
j = 0;
if (i >= maxStrCount) {
// extend array
char **newData = realloc(data, sizeof(char *) * (maxStrCount * 2));
if (newData == NULL) {
kill(data, maxStrCount);
return NULL;
}
maxStrCount *= 2;
data = newData;
for (int k = i; k < maxStrCount; k++) {
data[k] = malloc(sizeof(char) * maxStrLength);
if (data[k] == NULL) {
kill(data, k);
return NULL;
}
}
}
} else { // if not end of line
data[i][j] = ch;
j++;
if (j >= maxStrLength - 1) { // extend string
maxStrLength *= 2;
char *newStr = realloc(data[i], sizeof(char) * maxStrLength); // Here it crashes
if (newStr == NULL) {
kill(data, maxStrCount);
return NULL;
}
data[i] = newStr;
}
}
}
if (j > 0) { // in case of file doesn't end with empty line
data[i][j] = '\0';
i++;
}
if (i == 0) { // in case of empty input
kill(data, maxStrCount);
return NULL;
}
*strCount = i;
*allocatedCount = maxStrCount;
return data;
}
The crash appears on the following input:
Lorem ipsum dolor sit
amet, consectetur
adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua
It happens like this: It reads "Lorem ips", then realloc is called, then reads "Lorem ipsum dolor s", then realloc is called again, all fine. Then it reads "amet, consectetur" (2-nd line) and "adipiscing elit, sed do eiusmod tempor " (3-rd line), then tries to realloc and crashes.
I watched all this trying to debug, but I still have no idea why does it crash.

Answer 1

You are sharing the variable maxStrLength between all strings.
You are reallocating the buffer for the 2-nd line and increasing that maxStrLength; however, when you are reading the next line, it's buffer is smaller, so you are writing into it out-of-bounds here:
data[i][j] = ch;