Malloc error while inserting an element in a red black tree

#include<stdio.h> #include<stdlib.h> typedef struct treenode{ int elem; int color; struct treenode *left,*right,*parent; }treenode_t; treenode_t *create_node(int elem){ treenode_t *newnode=(treenode_t *)malloc(sizeof(treenode_t *)); newnode->elem=elem; newnode->left=NULL; newnode->right=NULL; newnode->color=0; newnode->parent=NULL; return newnode; } void insert(treenode_t **node,int elem){ if(*node==NULL){ *node=create_node(elem); }else{ treenode_t *store_parent; treenode_t *ptr; ptr=*node; while(ptr!=NULL){ store_parent=ptr; if(elem<ptr->elem){ if(ptr->left==NULL){ ptr->left=create_node(elem); (ptr->left)->parent=store_parent; (ptr->left)->color=1; } ptr=ptr->left; } else if(elem>ptr->elem){ if(ptr->right==NULL){ ptr->right=create_node(elem); (ptr->right)->parent=store_parent; (ptr->right)->color=1; } ptr=ptr->right; } } } } void print_tree(treenode_t *node){ if(node==NULL) return; print_tree(node->left); printf("%d\n",node->elem); print_tree(node->right); } void main(){ treenode_t *root=NULL; insert(&root,10); insert(&root,5); insert(&root,14); print_tree(root); } 

I am able to insert the first element but the second time the malloc fails.

Using GDB: When i use gdb i found that once i have created the first node(the root of the tree), when i go insert the second element i.e. 5 the line ptr->left=create_node(elem) redirects to the function create_node().The address which is allocated to malloc is the same as that is stored in the root which results in the error.

I get the following error:

a.out: malloc.c:2372: sysmalloc: Assertion `(old_top == (((mbinptr) (((char *) &((av)->bins[((1) - 1) * 2])) - __builtin_offsetof (struct malloc_chunk, fd)))) && old_size == 0) || ((unsigned long) (old_size) >= (unsigned long)((((__builtin_offsetof (struct malloc_chunk, fd_nextsize))+((2 *(sizeof(size_t))) - 1)) & ~((2 *(sizeof(size_t))) - 1))) && ((old_top)->size & 0x1) && ((unsigned long) old_end & pagemask) == 0)' failed.

Program received signal SIGABRT, Aborted. 0x00007ffff7a4af79 in __GI_raise (sig=sig@entry=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:56 56 ../nptl/sysdeps/unix/sysv/linux/raise.c: No such file or directory.

Now do i have to change the address the of the memory that is allocated by malloc(if so,how?) or is there some other problem in the code?