On Thu, 29 Jan 2015 18:11:46 +0300 Andrey Ryabinin <a.ryabinin@xxxxxxxxxxx> wrote: > This patch adds arch specific code for kernel address sanitizer. > > 16TB of virtual addressed used for shadow memory. > It's located in range [ffffec0000000000 - fffffc0000000000] > between vmemmap and %esp fixup stacks. > > At early stage we map whole shadow region with zero page. > Latter, after pages mapped to direct mapping address range > we unmap zero pages from corresponding shadow (see kasan_map_shadow()) > and allocate and map a real shadow memory reusing vmemmap_populate() > function. > > Also replace __pa with __pa_nodebug before shadow initialized. > __pa with CONFIG_DEBUG_VIRTUAL=y make external function call (__phys_addr) > __phys_addr is instrumented, so __asan_load could be called before > shadow area initialized. > > ... > > --- a/lib/Kconfig.kasan > +++ b/lib/Kconfig.kasan > @@ -5,6 +5,7 @@ if HAVE_ARCH_KASAN > > config KASAN > bool "AddressSanitizer: runtime memory debugger" > + depends on !MEMORY_HOTPLUG > help > Enables address sanitizer - runtime memory debugger, > designed to find out-of-bounds accesses and use-after-free bugs. That's a significant restriction. It has obvious runtime implications. It also means that `make allmodconfig' and `make allyesconfig' don't enable kasan, so compile coverage will be impacted. This wasn't changelogged. What's the reasoning and what has to be done to fix it? -- 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>