Question

running my program with gdb I get this:

fem.o: malloc.c:3096: 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. 0xb7fe1424 in
__kernel_vsyscall ()

I found that this error arises after this code:

problem->y0 = (double *)calloc(n_tot, sizeof(double));

problem is a structure which has double *y0 as member.

Previously in the function, I do this

problem = (fem_problem *)calloc(1, sizeof(fem_problem));

and I don’t get any error neither problem == NULL.

some suggestion?

ADD:

I already checked the content of n_tot, it has the right number

Answer 1

There could be any number of problems, for example:

• The value of n_tot could be garbage.

• You have written outside of an allocated block, and in doing so you have destroyed data structures used to maintain the heap.