Receive SIGSEGV in _IO_vfscanf_internal() - c

Question

My program will compile and run normally, however, when I run the program through GDB, I receive a SIGSEGV, Segmentation fault
(0x0000003ec945352f in _IO_vfscanf_internal () from /lib64/libc.so.6)
after the fscanf in my code fills a node of a linked list. What causes the segmentation fault in GDB but not when I run my program?
(gdb) s
90 fscanf(fp,"%s %s %d %d", newNode->record_->first_name_, newNode->record_->last_name_, &newNode->record_->student_id_, &newNode->record_->student_age_);
(gdb) s
Program received signal SIGSEGV, Segmentation fault.
0x0000003ec945352f in _IO_vfscanf_internal () from /lib64/libc.so.6
#include <stdio.h>
#include <stdlib.h>
struct student_record_node
{
struct student_record* record_;
struct student_record_node* next_;
};
struct student_record
{
int student_id_;
int student_age_;
char first_name_[21];
char last_name_[21];
};
void parseFile();
struct student_record_node* student_record_allocate();
void appendNode(struct student_record_node* head, struct student_record_node* newNode);
void printNode(struct student_record_node* node);
void student_record_node_deallocate(struct student_record_node* node);
void printNodeList(struct student_record_node* head);
void swap(struct student_record_node** node1, struct student_record_node** node2);
void sortByAge(struct student_record_node** recordsHead);
void sortById(struct student_record_node** recordsHead);
void freeNodeList(struct student_record_node* head);
void student_record_node_deallocate(struct student_record_node* node);
int main(int argc, char* argv[])
{
struct student_record_node* node = student_record_allocate();
struct student_record_node** head = &node;
parseFile(argv[1], head);
printf("Before sorting...\n");
printNodeList(*head);
sortByAge(head);
printf("Sorting by age...\n");
printNodeList(*head);
sortById(head);
printf("Sorting by id...\n");
printNodeList(*head);
freeNodeList(*head);
}
struct student_record_node* student_record_allocate()
{
struct student_record_node* newNode;
newNode = calloc(1, sizeof(struct student_record_node));
if (newNode == NULL)
{
printf("No memory allocated for newNode");
exit(1);
}
newNode->record_ = calloc(1, sizeof(struct student_record));
if (newNode->record_ == NULL)
{
printf("No memory allocated for record_");
exit(1);
}
newNode->next_ = NULL;
return newNode;
}
void parseFile(char* filename, struct student_record_node** head)
{
int i = 0;
struct student_record_node* newNode = *head;
FILE* fp;
fp = fopen(filename,"r");
if (fp == NULL)
{
printf("Could not read file\n");
exit(1);
}
while(1)
{
if(newNode != *head)
{
newNode = student_record_allocate();
appendNode(*head, newNode);
}
fscanf(fp,"%s %s %d %d", newNode->record_->first_name_, newNode->record_->last_name_, &newNode->record_->student_id_, &newNode->record_->student_age_);
if(newNode == *head)
{
newNode = NULL;
}
if(feof(fp))
{
break;
}
}
fclose(fp);
}
void appendNode(struct student_record_node* head, struct student_record_node* newNode)
{
int i = 1;
struct student_record_node* current = head;
while (i)
{
if (current->next_ == NULL)
{
current->next_ = newNode;
i = 0;
}
current = current->next_;
}
}
void printNode(struct student_record_node* node)
{
printf("struct student_record_node:\n");
printf("\tStudent first name: %s\n", node->record_->first_name_);
printf("\tStudent last name: %s\n", node->record_->last_name_);
printf("\tStudent id: %d\n", node->record_->student_id_);
printf("\tStudent age: %d\n", node->record_->student_age_);
}
void printNodeList(struct student_record_node* head)
{
struct student_record_node* current = head;
while (current->next_ != NULL)
{
printNode(current);
current = current->next_;
}
printf("\n");
}
void swap(struct student_record_node** node1, struct student_record_node** node2)
{
struct student_record* newNode;
struct student_record_node* big = *node2;
struct student_record_node* small = *node1;
newNode = big->record_;
big->record_ = small->record_;
small->record_ = newNode;
}
void sortByAge(struct student_record_node** recordsHead)
{
int i,j;
struct student_record_node* current = *recordsHead;
struct student_record_node* next = *recordsHead;
while (current->next_->next_ != NULL)
{
next = current;
while (next->next_->next_ != NULL)
{
if (next->next_->record_->student_age_ <= next->record_->student_age_)
{
swap(&next->next_, &next );
}
next = next->next_;
}
current = current->next_;
}
}
void sortById(struct student_record_node** recordsHead)
{
int i = 0;
struct student_record_node* current = *recordsHead;
struct student_record_node* beginning = *recordsHead;
struct student_record_node* next = *recordsHead;
while (current->next_->next_ != NULL)
{
next = beginning;
while(next->next_->next_ !=NULL)
{
if (next->next_->record_->student_id_ <= next->record_->student_id_)
{
swap(&next->next_, &next);
}
next = next->next_;
}
current = current->next_;
}
}
void student_record_node_deallocate(struct student_record_node* node)
{
struct student_record_node* tmp;
tmp = node;
free(tmp->record_);
free(tmp);
}
void freeNodeList(struct student_record_node* head)
{
while (head != NULL)
{
student_record_node_deallocate(head);
head = head->next_;
}
}