On Tue, Dec 01, 2020 at 11:45:47PM +0200, Topi Miettinen wrote:
> + /* Randomize allocation */
> + if (randomize_vmalloc) {
> + voffset = get_random_long() & (roundup_pow_of_two(vend - vstart) - 1);
> + voffset = PAGE_ALIGN(voffset);
> + if (voffset + size > vend - vstart)
> + voffset = vend - vstart - size;
> + } else
> + voffset = 0;
> +
> /*
> * If an allocation fails, the "vend" address is
> * returned. Therefore trigger the overflow path.
> */
> - addr = __alloc_vmap_area(size, align, vstart, vend);
> + addr = __alloc_vmap_area(size, align, vstart + voffset, vend);
> spin_unlock(&free_vmap_area_lock);
What if there isn't any free address space between vstart+voffset and
vend, but there is free address space between vstart and voffset?
Seems like we should add:
addr = __alloc_vmap_area(size, align, vstart + voffset, vend);
+ if (!addr)
+ addr = __alloc_vmap_area(size, align, vstart, vend);
spin_unlock(&free_vmap_area_lock);
