C code to create a linked list segmentation fault - c

Question

Ok, so for my homework I have a function that creates a linked list from file input and it's like a calendar, so it reads in a date and title from a file. I'm using a head node that is globally declared to make it
easier to work with other functions.
This is my node struct:
typedef struct event_t{
char title[20];
event_date_t date;
struct event_t *next;
}event_t;
event_date_t is just a simple struct for the date
Here's the function:
void insert_events_linked_list(FILE *file, int n){
//printf("LL function started\n"); //self-explanatory test line
event_t last;
head.next = &last;
int i;
//This loop will create a ll of the specified length
for(i=0; i<n; i++){
event_t *last = malloc(sizeof(event_t));
int title_test = fscanf(file, "%20s%*c", last->title);
printf("%s\n", last->title); //test line to make sure names are grabbed properly
//This skips the rest of the event and prints error message if title is too long
if(title_test != 1){
fscanf(file, "%*s %*d %*d");
printf("Error: LL event %d title too long\n", i++);
continue;
}
else{
fscanf(file, "%d %d", &last->date.month, &last->date.day);
last = last->next;
}
}
printf("Loop exited");
}
The test line prints all the titles, but it shows a segmentation fault and aborts before printing "Loop exited"

Answer 1

This line of your code,
event_t *last = malloc(sizeof(event_t));
will declare a brand new last every time the for loops back. Declare it as static and adjust your code accordingly, and there should no longer be any problem.
Demo
for (i=0;i<5;i++){
int x=6;
x++;
printf("%d ",x);
}
Output
7 7 7 7 7
You should see the problem.

Answer 2

The test line prints all the titles, but it shows a segmentation fault and aborts before printing "Loop exited"
There are many bugs in your program. You should read this post. You should also learn to use a debugger.
I suspect that the reason Loop exited is not printed is that you didn't terminate it with the newline, and so printf is waiting for you to complete a line or call fflush. By default, printf output is line buffered. That is one of the reasons you should always use fprintf(stderr, ...) instead. stderr (by default) is unbuffered.
On to bugs.
You have two variables called last in the same scope. This is almost never a good idea.
This statement:
head.next = &last;
assigned an address of a local variable to a global head pointer. After the current function returns, that address will become invalid, and this is almost certainly not what you intended. In particular, head.next never points to any memory you malloc (and leak!) in the loop.
Your loop looks like this:
for (...) {
event_t *last = malloc(sizeof(event_t)); // last->next is uninitialized
...
last = last->next; // leak the memory allocated above
// by overwriting the pointer with garbage
}
That is also clearly not what you intended.
Here is one way to build a linked list incrementally:
event_t **link = &head.next;
for (...) {
event_t *ev = calloc(...); // Initializes ev->next to NULL.
// Fill the rest of ev ...
// Link it into the list:
*link = ev;
link = &ev->next;
}