From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7D42AC04FF3 for ; Mon, 24 May 2021 10:37:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5A3306109F for ; Mon, 24 May 2021 10:37:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232634AbhEXKjQ (ORCPT ); Mon, 24 May 2021 06:39:16 -0400 Received: from foss.arm.com ([217.140.110.172]:40690 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232574AbhEXKjN (ORCPT ); Mon, 24 May 2021 06:39:13 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 8556531B; Mon, 24 May 2021 03:37:45 -0700 (PDT) Received: from C02TD0UTHF1T.local (unknown [10.57.38.161]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D82B33F719; Mon, 24 May 2021 03:37:43 -0700 (PDT) Date: Mon, 24 May 2021 11:37:40 +0100 From: Mark Rutland To: Jisheng Zhang Cc: Catalin Marinas , Will Deacon , Marco Elver , Alexander Potapenko , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] arm64: mm: don't use CON and BLK mapping if KFENCE is enabled Message-ID: <20210524103740.GD1040@C02TD0UTHF1T.local> References: <20210524153659.58a707a9@xhacker.debian> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210524153659.58a707a9@xhacker.debian> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, May 24, 2021 at 03:36:59PM +0800, Jisheng Zhang wrote: > Fix below warning if KFENCE=y but RODATA_FULL=n: > > [ 0.000000] ------------[ cut here ]------------ > [ 0.000000] WARNING: CPU: 0 PID: 0 at mm/memory.c:2462 apply_to_pmd_range+0xec/0x190 > [ 0.000000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.13.0-rc1+ #10 > [ 0.000000] Hardware name: linux,dummy-virt (DT) > [ 0.000000] pstate: 600000c5 (nZCv daIF -PAN -UAO -TCO BTYPE=--) > [ 0.000000] pc : apply_to_pmd_range+0xec/0x190 > [ 0.000000] lr : __apply_to_page_range+0x94/0x170 > [ 0.000000] sp : ffffffc010573e20 > [ 0.000000] x29: ffffffc010573e20 x28: ffffff801f400000 x27: ffffff801f401000 > [ 0.000000] x26: 0000000000000001 x25: ffffff801f400fff x24: ffffffc010573f28 > [ 0.000000] x23: ffffffc01002b710 x22: ffffffc0105fa450 x21: ffffffc010573ee4 > [ 0.000000] x20: ffffff801fffb7d0 x19: ffffff801f401000 x18: 00000000fffffffe > [ 0.000000] x17: 000000000000003f x16: 000000000000000a x15: ffffffc01060b940 > [ 0.000000] x14: 0000000000000000 x13: 0098968000000000 x12: 0000000098968000 > [ 0.000000] x11: 0000000000000000 x10: 0000000098968000 x9 : 0000000000000001 > [ 0.000000] x8 : 0000000000000000 x7 : ffffffc010573ee4 x6 : 0000000000000001 > [ 0.000000] x5 : ffffffc010573f28 x4 : ffffffc01002b710 x3 : 0000000040000000 > [ 0.000000] x2 : ffffff801f5fffff x1 : 0000000000000001 x0 : 007800005f400705 > [ 0.000000] Call trace: > [ 0.000000] apply_to_pmd_range+0xec/0x190 > [ 0.000000] __apply_to_page_range+0x94/0x170 > [ 0.000000] apply_to_page_range+0x10/0x20 > [ 0.000000] __change_memory_common+0x50/0xdc > [ 0.000000] set_memory_valid+0x30/0x40 > [ 0.000000] kfence_init_pool+0x9c/0x16c > [ 0.000000] kfence_init+0x20/0x98 > [ 0.000000] start_kernel+0x284/0x3f8 > > Fixes: 840b23986344 ("arm64, kfence: enable KFENCE for ARM64") > Signed-off-by: Jisheng Zhang It would be good if the commit message could explain the problem more thoroughly, e.g. | When we added KFENCE support for arm64, we intended that it would | force the entire linear map to be mapped at page granularity, but we | only enforced this in arch_add_memory() and not in map_mem(), so | memory mapped at boot time can be mapped at a larger granularity. | | When booting a kernel with KFENCE=y and RODATA_FULL=n, this results in | the following WARNING at boot: | | < warning here > With that: Acked-by: Mark Rutland Mark. > --- > arch/arm64/mm/mmu.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c > index 6dd9369e3ea0..89b66ef43a0f 100644 > --- a/arch/arm64/mm/mmu.c > +++ b/arch/arm64/mm/mmu.c > @@ -515,7 +515,8 @@ static void __init map_mem(pgd_t *pgdp) > */ > BUILD_BUG_ON(pgd_index(direct_map_end - 1) == pgd_index(direct_map_end)); > > - if (rodata_full || crash_mem_map || debug_pagealloc_enabled()) > + if (rodata_full || crash_mem_map || debug_pagealloc_enabled() || > + IS_ENABLED(CONFIG_KFENCE)) > flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; > > /* > -- > 2.31.0 >