On 01/30/2015 02:12 AM, Andrew Morton wrote: > On Thu, 29 Jan 2015 18:11:57 +0300 Andrey Ryabinin <a.ryabinin@xxxxxxxxxxx> wrote: > >> For instrumenting global variables KASan will shadow memory >> backing memory for modules. So on module loading we will need >> to allocate shadow memory and map it at exact virtual address. > > I don't understand. What does "map it at exact virtual address" mean? > I mean that if module_alloc() returned address x, than shadow memory should be mapped exactly at address kasan_mem_to_shadow(x). >> __vmalloc_node_range() seems like the best fit for that purpose, >> except it puts a guard hole after allocated area. > > Why is the guard hole a problem? > Because of guard hole in shadow some future allocations of shadow memory will fail. Requested address ( kasan_mem_to_shadow(x) ) will be already occupied by guard hole of previous allocation. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>