On 01/02/18 02:00, Christopher Lameter wrote:
On Tue, 30 Jan 2018, Igor Stoppa wrote:
quoted
@@ -1769,6 +1774,9 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align,
kmemleak_vmalloc(area, size, gfp_mask);
+ for (page_counter = 0; page_counter < area->nr_pages; page_counter++)
+ area->pages[page_counter]->area = area;
+
return addr;
Well this introduces significant overhead for large sized allocation. Does
this not matter because the areas are small?
Relatively significant?
I do not object to your comment, but in practice i see that:
- vmalloc is used relatively little
- allocations do not seem to be huge
- there seem to be way larger overheads in the handling of virtual pages
(see my proposal for the LFS/m summit, about collapsing struct
vm_struct and struct vmap_area)
Would it not be better to use compound page allocations here?
page_head(whatever) gets you the head page where you can store all sorts
of information about the chunk of memory.
Can you please point me to this function/macro? I don't seem to be able
to find it, at least not in 4.15
During hardened user copy permission check, I need to confirm if the
memory range that would be exposed to userspace is a legitimate
sub-range of a pmalloc allocation.
So, I start with the pair (address, size) and I must end up to something
I can compare it against.
The idea here is to pass through struct_page and then the related
vm_struct/vmap_area, which already has the information about the
specific chunk of virtual memory.
I cannot comment on your proposal because I do not know where to find
the reference you made, or maybe I do not understand what you mean :-(
--
igor
--
To unsubscribe from this list: send the line "unsubscribe linux-security-module" in
the body of a message to majordomo at vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html