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=-8.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,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 8BF1DC04FF3 for ; Mon, 24 May 2021 11:13:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 664AC61151 for ; Mon, 24 May 2021 11:13:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232643AbhEXLPX (ORCPT ); Mon, 24 May 2021 07:15:23 -0400 Received: from foss.arm.com ([217.140.110.172]:41108 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232625AbhEXLPT (ORCPT ); Mon, 24 May 2021 07:15:19 -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 3C05331B; Mon, 24 May 2021 04:13:51 -0700 (PDT) Received: from C02TD0UTHF1T.local (unknown [10.57.38.161]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 5C14E3F719; Mon, 24 May 2021 04:13:49 -0700 (PDT) Date: Mon, 24 May 2021 12:13:46 +0100 From: Mark Rutland To: Marco Elver Cc: Jisheng Zhang , Catalin Marinas , Will Deacon , Alexander Potapenko , Linux ARM , LKML Subject: Re: [PATCH] arm64: mm: don't use CON and BLK mapping if KFENCE is enabled Message-ID: <20210524111346.GE1040@C02TD0UTHF1T.local> References: <20210524153659.58a707a9@xhacker.debian> <20210524103740.GD1040@C02TD0UTHF1T.local> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, May 24, 2021 at 12:43:56PM +0200, Marco Elver wrote: > On Mon, 24 May 2021 at 12:37, Mark Rutland wrote: > > > > 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 > > We also need "Cc: stable@vger.kernel.org", right? That would be a good idea, yes. I can't recall whether "Fixes" alone is intended to be sufficient or not to trigger a backport. Mark. > Acked-by: Marco Elver > > Thank you both! > > -- Marco