Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752856AbbGBH5H (ORCPT ); Thu, 2 Jul 2015 03:57:07 -0400 Received: from mail-wg0-f49.google.com ([74.125.82.49]:36700 "EHLO mail-wg0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751456AbbGBH44 (ORCPT ); Thu, 2 Jul 2015 03:56:56 -0400 Date: Thu, 2 Jul 2015 09:56:50 +0200 From: Ingo Molnar To: Andrey Ryabinin Cc: Ingo Molnar , "H. Peter Anvin" , Thomas Gleixner , x86@kernel.org, Andrey Konovalov , Andrew Morton , Borislav Petkov , Alexander Popov , Dmitry Vyukov , Alexander Potapenko , linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH 1/5] x86_64: fix kasan shadow region page tables Message-ID: <20150702075650.GA27936@gmail.com> References: <1435654466-8714-1-git-send-email-a.ryabinin@samsung.com> <1435654811-8915-1-git-send-email-a.ryabinin@samsung.com> <1435654811-8915-2-git-send-email-a.ryabinin@samsung.com> <20150701090740.GA16645@gmail.com> <5593D969.6020408@samsung.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5593D969.6020408@samsung.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2398 Lines: 68 * Andrey Ryabinin wrote: > On 07/01/2015 12:07 PM, Ingo Molnar wrote: > > > > * Andrey Ryabinin wrote: > > > >> diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c > >> index 5a46681..f129a9a 100644 > >> --- a/arch/x86/kernel/head64.c > >> +++ b/arch/x86/kernel/head64.c > >> @@ -161,11 +161,12 @@ asmlinkage __visible void __init x86_64_start_kernel(char * real_mode_data) > >> /* Kill off the identity-map trampoline */ > >> reset_early_page_tables(); > >> > >> - kasan_map_early_shadow(early_level4_pgt); > >> - > >> - /* clear bss before set_intr_gate with early_idt_handler */ > >> clear_bss(); > >> > >> + clear_page(init_level4_pgt); > >> + > >> + kasan_early_init(); > >> + > >> for (i = 0; i < NUM_EXCEPTION_VECTORS; i++) > >> set_intr_gate(i, early_idt_handler_array[i]); > >> load_idt((const struct desc_ptr *)&idt_descr); > >> @@ -177,12 +178,9 @@ asmlinkage __visible void __init x86_64_start_kernel(char * real_mode_data) > >> */ > >> load_ucode_bsp(); > >> > >> - clear_page(init_level4_pgt); > >> /* set init_level4_pgt kernel high mapping*/ > >> init_level4_pgt[511] = early_level4_pgt[511]; > >> > >> - kasan_map_early_shadow(init_level4_pgt); > >> - > >> x86_64_start_reservations(real_mode_data); > >> } > >> > > > > So this changes generic code (moves the clear_page(init_level4_pgt) call), but the > > changelog claims it's a KASAN-specific change. > > > > Please split this into two patches: the first one does the generic change, the > > second one the KASAN specific one. > > > > Hm... We will need to backport that generic change to stable, because second change depends on it. > So, maybe split this on three changes: > > #1 fix kasan page tables (without touching clear_page() or kasan_map_early_shadow(init_level4_pgt)) > #2 generic move clear_page() > #3 clean up kasan initialization (move kasan_map_early_shadow(init_level4_pgt)). > > Only #1 will have stable tag. Does that makes sense? I wouldn't overcomplicate it - just split it up and both patches can get the stable tag just fine... Thanks, Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/