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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DFCB9CA0EC4 for ; Tue, 12 Aug 2025 16:59:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=DxjcecEI7phcRYjWyLkZSnGEJwCBjNTRZZccT/msDU8=; b=Qyu9GyFNShTkADBaQsw3k20tQ+ sOPfRxM/itqy+M/Z/hURKZtl/cZN3uRH3zo2V+h8np/DvUwr6OBRSzYFTb8Bx1LrbkVM8sG6e9boB 6fDdo3D26kRlOuizdHIXJHuqCFsAwZq2o87L5zz414qs0VEy3rY8q9rfhwuF6w/pjWbgR/qW4XLN4 DQTv7nT05Y5WJmIBHNeJBcR0D9W4prPNrtwD1g6HHsfxzl/qxNFur7i77lhRlrwdb1xKLNxV5dcBi NR5In0rQJ8K2i+msKRK8q0GFKpHP3csalC6mk1HupenQsqDSxlhnKrahJ8Vf7f8mxN5Ua0Pd8Io5d JAl9E1tg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1ulsLY-0000000BUXh-3z5b; Tue, 12 Aug 2025 16:59:36 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1ulpDq-0000000Awuy-3lLy for linux-arm-kernel@lists.infradead.org; Tue, 12 Aug 2025 13:39:29 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1755005965; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=DxjcecEI7phcRYjWyLkZSnGEJwCBjNTRZZccT/msDU8=; b=KDTLkC4UeDYZx98A7Bs0g6wIxZ3tgZbAn4sVnRtM8LRDTkZxZoiwKlLqmX7OFTpU2/h7Yy aWhVj3VshYlsnnX/m008+xFqaB3paWSFb5vuQuBl5pbeLiMU7LbXCO16cXgprXGlSCWdY5 gR1eUe9giFHe+aitW29WMIitrhCTKnQ= Received: from mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-553-FY5fxrhNOyqPzbOI5L33kw-1; Tue, 12 Aug 2025 09:39:22 -0400 X-MC-Unique: FY5fxrhNOyqPzbOI5L33kw-1 X-Mimecast-MFC-AGG-ID: FY5fxrhNOyqPzbOI5L33kw_1755005958 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 5149919560B3; Tue, 12 Aug 2025 13:39:17 +0000 (UTC) Received: from localhost (unknown [10.72.112.156]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 7F8A819560AB; Tue, 12 Aug 2025 13:39:15 +0000 (UTC) Date: Tue, 12 Aug 2025 21:39:11 +0800 From: Baoquan He To: linux-mm@kvack.org, alexghiti@rivosinc.com, agordeev@linux.ibm.com, linux@armlinux.org.uk, linux-arm-kernel@lists.infradead.org, loongarch@lists.linux.dev, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, christophe.leroy@csgroup.eu, x86@kernel.org, chris@zankel.net, jcmvbkbc@gmail.com, linux-um@lists.infradead.org Cc: ryabinin.a.a@gmail.com, glider@google.com, andreyknvl@gmail.com, dvyukov@google.com, vincenzo.frascino@arm.com, akpm@linux-foundation.org, kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org, kexec@lists.infradead.org, sj@kernel.org, lorenzo.stoakes@oracle.com, elver@google.com, snovitoll@gmail.com Subject: Re: [PATCH v2 00/12] mm/kasan: make kasan=on|off work for all three modes Message-ID: References: <20250812124941.69508-1-bhe@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250812124941.69508-1-bhe@redhat.com> X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250812_063927_034157_7F3CB181 X-CRM114-Status: GOOD ( 27.03 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Forgot adding related ARCH mailing list or people to CC, add them. On 08/12/25 at 08:49pm, Baoquan He wrote: > Currently only hw_tags mode of kasan can be enabled or disabled with > kernel parameter kasan=on|off for built kernel. For kasan generic and > sw_tags mode, there's no way to disable them once kernel is built. > This is not convenient sometime, e.g in system kdump is configured. > When the 1st kernel has KASAN enabled and crash triggered to switch to > kdump kernel, the generic or sw_tags mode will cost much extra memory > for kasan shadow while in fact it's meaningless to have kasan in kdump > kernel. > > So this patchset moves the kasan=on|off out of hw_tags scope and into > common code to make it visible in generic and sw_tags mode too. Then we > can add kasan=off in kdump kernel to reduce the unneeded meomry cost for > kasan. > > Changelog: > ==== > v1->v2: > - Add __ro_after_init for __ro_after_init, and remove redundant blank > lines in mm/kasan/common.c. Thanks to Marco. > - Fix a code bug in when CONFIG_KASAN is unset, > this is found out by SeongJae and Lorenzo, and also reported by LKP > report, thanks to them. > - Add a missing kasan_enabled() checking in kasan_report(). This will > cause below KASAN report info even though kasan=off is set: > ================================================================== > BUG: KASAN: stack-out-of-bounds in tick_program_event+0x130/0x150 > Read of size 4 at addr ffff00005f747778 by task swapper/0/1 > > CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.16.0+ #8 PREEMPT(voluntary) > Hardware name: GIGABYTE R272-P30-JG/MP32-AR0-JG, BIOS F31n (SCP: 2.10.20220810) 09/30/2022 > Call trace: > show_stack+0x30/0x90 (C) > dump_stack_lvl+0x7c/0xa0 > print_address_description.constprop.0+0x90/0x310 > print_report+0x104/0x1f0 > kasan_report+0xc8/0x110 > __asan_report_load4_noabort+0x20/0x30 > tick_program_event+0x130/0x150 > ......snip... > ================================================================== > > - Add jump_label_init() calling before kasan_init() in setup_arch() in these > architectures: xtensa, arm. Because they currenly rely on > jump_label_init() in main() which is a little late. Then the early static > key kasan_flag_enabled in kasan_init() won't work. > > - In UML architecture, change to enable kasan_flag_enabled in arch_mm_preinit() > because kasan_init() is enabled before main(), there's no chance to operate > on static key in kasan_init(). > > Test: > ===== > In v1, I took test on x86_64 for generic mode, and on arm64 for > generic, sw_tags and hw_tags mode. All of them works well. > > In v2, I only tested on arm64 for generic, sw_tags and hw_tags mode, it > works. For powerpc, I got a BOOK3S/64 machine, while it says > 'KASAN not enabled as it requires radix' and KASAN is disabled. Will > look for other POWER machine to test this. > ==== > > Baoquan He (12): > mm/kasan: add conditional checks in functions to return directly if > kasan is disabled > mm/kasan: move kasan= code to common place > mm/kasan/sw_tags: don't initialize kasan if it's disabled > arch/arm: don't initialize kasan if it's disabled > arch/arm64: don't initialize kasan if it's disabled > arch/loongarch: don't initialize kasan if it's disabled > arch/powerpc: don't initialize kasan if it's disabled > arch/riscv: don't initialize kasan if it's disabled > arch/x86: don't initialize kasan if it's disabled > arch/xtensa: don't initialize kasan if it's disabled > arch/um: don't initialize kasan if it's disabled > mm/kasan: make kasan=on|off take effect for all three modes > > arch/arm/kernel/setup.c | 6 +++++ > arch/arm/mm/kasan_init.c | 6 +++++ > arch/arm64/mm/kasan_init.c | 7 ++++++ > arch/loongarch/mm/kasan_init.c | 5 ++++ > arch/powerpc/mm/kasan/init_32.c | 8 +++++- > arch/powerpc/mm/kasan/init_book3e_64.c | 6 +++++ > arch/powerpc/mm/kasan/init_book3s_64.c | 6 +++++ > arch/riscv/mm/kasan_init.c | 6 +++++ > arch/um/kernel/mem.c | 6 +++++ > arch/x86/mm/kasan_init_64.c | 6 +++++ > arch/xtensa/kernel/setup.c | 1 + > arch/xtensa/mm/kasan_init.c | 6 +++++ > include/linux/kasan-enabled.h | 18 ++++++------- > mm/kasan/common.c | 25 ++++++++++++++++++ > mm/kasan/generic.c | 20 +++++++++++++-- > mm/kasan/hw_tags.c | 35 ++------------------------ > mm/kasan/init.c | 6 +++++ > mm/kasan/quarantine.c | 3 +++ > mm/kasan/report.c | 4 ++- > mm/kasan/shadow.c | 23 ++++++++++++++++- > mm/kasan/sw_tags.c | 9 +++++++ > 21 files changed, 165 insertions(+), 47 deletions(-) > > -- > 2.41.0 >