Null-pointer dereference bug in nano-malloc

Hi,
It appears that commit 84d068971 introduced a null-pointer dereference in
nano-malloc when the following two conditions are met:

1). The free_list has no items (= NULL).
2). The call to sbrk_aligned returns -1 (failure).

On line 325 of newlib/libc/stdlib/nano-mallocr.c, there is a check:

if ((char *)p + p->size == (char *)_SBRK_R(RCALL 0))
{

If the two conditions are met, then p = free_list = NULL so p->size will be
a null-pointer dereference. Is this something that's known/being tracked
anywhere?
Cyril