malloc - C - writing buffer into a file then FREEing the buffer cause segfault -

i'm writing buffer binary file. code in following :

file *outwav = fopen(outwav_path, "wb"); if(!outwav) {     fprintf(stderr, "can't open file %s writing.\n", outwav_path);     exit(1); } 

[...]

//create sample buffer short *samples = malloc((loopcount*(blockamount-looppos)+looppos) << 5); if(!samples) {     fprintf(stderr, "error : can't allocate memory.\n");     exit(1); } 

[...]

fwrite(samples, 2, 16*k, outwav);   //write samplebuffer file  fflush(outwav); fclose(outwav); free(samples); 

the last free() call causes me random segfaults. after several headaches thought because fwrite call execute after delay, , read freed memory. added fflush call, yet, problem still occurs.

the way rid of not free memory , let os me. supposed bad practice though, i'd rather ask if there no better solution.

before asks, yes check file opened correctly, , yes test memory allocated properly, , no, don't touch returned pointers in way.

once fwrite returns free whatever want buffer. can remove fflush call.

it sounds buffer overflow error in totally unrelated part of program writing on book-keeping information free needs work. run program under tool valgrind find out if problem , find part of program has buffer overflow.