Question

I have a structure defined like so:

typedef struct {
 int n;
 int *n_p;
 void **list_pp;
 size_t rec_size;
 int n_buffs;
 size_t buff_size
} fl_hdr_type;

and in my code I Have a function for initlialization that has the following

fl_hdr_type *fl_hdr;
fl_hdr = malloc(sizeof(fl_hdr_type) + (buff_size_n * rec_size_n));

where those buffer size are passed in to the function to allow space for the buffers as well.

The size is pretty small typically..100*50 or something like that..plenty of memory on this system to allocate it.
I can’t actually post the stack trace because this code is on another network, but some information pulled from dbx on the core file:

buff_size_n = 32, rec_size_n = 186

and the stack..line numbers from malloc.c

 t_splay:861
 t_delete:796
 realfree: 531
 cleanfree:945
 _malloc:230
 _malloc:186

Any ideas why this fails?

Answer 1

Try running your program through valgrind, see what it reports. It’s possible in some other part of the program you have corrupted free lists or something else malloc looks at.