On Mon, Aug 24, 2015 at 05:15:22PM +0300, Andrey Ryabinin wrote: > Yes, ~130Mb (3G/1G split) should work. 512Mb shadow is optional. > The only advantage of 512Mb shadow is better handling of user memory > accesses bugs > (access to user memory without copy_from_user/copy_to_user/strlen_user etc > API).
No need for that to be handed by KASan. I have patches in linux-next, now acked by Will, which prevent the kernel accessing userspace with zero memory footprint. No need for remapping, we have a way to quickly turn off access to userspace mapped pages on non-LPAE 32-bit CPUs. (LPAE is not supported yet - Catalin will be working on that using the hooks I'm providing once he returns.) This isn't a debugging thing, it's a security hardening thing. Some use-after-free bugs are potentially exploitable from userspace. See the recent blackhat conference paper. -- FTTC broadband for 0.8mile line: currently at 10.5Mbps down 400kbps up according to speedtest.net. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
