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Message-Id: <20160616060538.GA3923@osiris> Date: Thu, 16 Jun 2016 08:05:38 +0200 From: Heiko Carstens <heiko.carstens@...ibm.com> To: Andy Lutomirski <luto@...nel.org> Cc: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, x86@...nel.org, Borislav Petkov <bp@...en8.de>, Nadav Amit <nadav.amit@...il.com>, Kees Cook <keescook@...omium.org>, Brian Gerst <brgerst@...il.com>, "kernel-hardening@...ts.openwall.com" <kernel-hardening@...ts.openwall.com>, Linus Torvalds <torvalds@...ux-foundation.org>, Josh Poimboeuf <jpoimboe@...hat.com> Subject: Re: [PATCH 00/13] Virtually mapped stacks with guard pages (x86, core) On Wed, Jun 15, 2016 at 05:28:22PM -0700, Andy Lutomirski wrote: > Since the dawn of time, a kernel stack overflow has been a real PITA > to debug, has caused nondeterministic crashes some time after the > actual overflow, and has generally been easy to exploit for root. > > With this series, arches can enable HAVE_ARCH_VMAP_STACK. Arches > that enable it (just x86 for now) get virtually mapped stacks with > guard pages. This causes reliable faults when the stack overflows. > > If the arch implements it well, we get a nice OOPS on stack overflow > (as opposed to panicing directly or otherwise exploding badly). On > x86, the OOPS is nice, has a usable call trace, and the overflowing > task is killed cleanly. Do you have numbers which reflect the performance impact of this change?
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