c - *** Error in `python': munmap_chunk(): invalid pointer: 0x00007fdfb8c28950 *** -

i want write c-extension python, can see below ,the aim of code calculate euclidean-dist 2 lists of float.

the c code:

#include <python2.7/python.h> #include <math.h>  static pyobject* cutil_euclidean_dist(pyobject* self, pyobject* args) {     pyobject *seq_a, *seq_b;     int n;     float * array_a,* array_b;     pyobject *item;      printf("prepare check input");      pyarg_parsetuple(args,"ioo", &n , &seq_a, &seq_b);     if (!pysequence_check(seq_a) || !pysequence_check(seq_b)) {        pyerr_setstring(pyexc_typeerror, "expected sequence");        return null;     }      array_a =(float *)malloc(sizeof(float)*n);     array_b =(float *)malloc(sizeof(float)*n);        if (null == array_a || null == array_b){         pyerr_setstring(pyexc_typeerror, "malloc failed!");         return null;     }      printf("%d",array_a==null);     printf("%d",array_b==null);      printf("malloc yes ");     printf("n=%d",n);      int i;     for(i=0;i<n;i++){         printf("111");          item = pysequence_getitem(seq_a,i);          printf("after item");         if (!pyfloat_check(item)) {             printf("in float check");             free(array_a);  /* free memory before leaving */             free(array_b);             free(seq_a);             free(seq_b);             pyerr_setstring(pyexc_typeerror, "expected sequence of float");             return null;         }         array_a[i] = pyfloat_asdouble(item);          printf("a=%f",array_a[i]);          py_decref(item);          item = pysequence_getitem(seq_b,i);         if(!pyfloat_check(item)) {             free(array_a);             free(array_b);             free(seq_a);             free(seq_b);             pyerr_setstring(pyexc_typeerror, "expected sequence of float");           }         array_b[i] = pyfloat_asdouble(item);         py_decref(item);     }      printf("array analyze yes");      double sum = 0;     for(i=0;i<n;i++){         double delta = array_a[i] - array_b[i];         sum += delta * delta;     }      free(array_a);     free(array_b);     free(seq_a);     free(seq_b);      return py_buildvalue("d",sqrt(sum)); }  static pymethoddef cutil_methods[] = {     {"c_euclidean_dist",        (pycfunction)cutil_euclidean_dist,meth_varargs,null},     {null,null,0,null} };  pymodinit_func initcutil(void) {     py_initmodule3("cutil", cutil_methods, "liurui's c extension     python"); }  

the python code:

import cutil cutil.c_euclidean_dist(2,[1.0,1.0],[2.0,2.0]) 

the result:

*** error in `python': munmap_chunk(): invalid pointer: 0x00007fdfb8c28950 ***  (core dumped) 

so can not succeed in calling function.

who can me problem? lot

i not know what's wrong it.

by way: when complie code, gcc asked me add -fpic , when add -fpic,the says gcc can not find python.h changed:

#include <python.h> 

into this:

#include <python2.7/python.h> 

then ok

when comment 2 sentences, code runs well:

free(seq_a); free(seq_b); 

but think without 2 sentences , there memory leak because seq_a , seq_b not freed

you can use free() deallocate memory allocated using malloc().

seq_a , seq_b incorrectly trying free not allocated via malloc.

also, should check out pyobject , reference counting chapter in python docs.