From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0C257186294 for ; Tue, 5 Aug 2025 06:23:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754375030; cv=none; b=rjpcjUShaG2BDF+j8Add/9pPf8VsPUCKQBLeYwb+2oejYt6oTDxDcCpjLa0j2BX4bWDqecMY52I/vn9nTnidvaKCzG6qbYskFtHIlIl3ZC9aY0gcfkeM+7KWIyXRiVX9Sa/b9zim622Shdm1ZvNdFLuF8QQEP7NSrDDvKDpIGao= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754375030; c=relaxed/simple; bh=HEPYGvI1vk3cetbRLjPfD2HI7d3WgP0RuNbGbhuWcX4=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-type; b=RmnYwfvXlmPPoWDaWeeEv0o2fcdZvhSppWSiTHPfAUYrrtA1t+E1QY6BzrTQbZDuE6/gb+dA7q+CtxumkyDOUETsnd/BzHC5Y7zMC4ENgwqHVM0ihVMaC1DF2m+pfNK7L2dNYibHbnJLmeeWDONxg09qCRz2kCiUBXaeF1gkDIk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=eTm92kw5; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="eTm92kw5" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1754375027; 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: content-transfer-encoding:content-transfer-encoding; bh=YSXKdaD3IZAs8uieY7LPn8yhD3PkW5u9fBN/Is1bw+s=; b=eTm92kw5ySyzMtRHOyf9QLC4RimZyRy3gIWPMGnX+6p2dFAaHUn1NpobeGcvqdgcLqNEn1 9yDN/5NtP8/Kmyn+KbkfePu6D/e1wu5moJnIPmuGZnVBPCq00lZEclnL+WtdJrFrPFnVJp KSAf0ek56MhHNBo9pnEQbtNb+ARFW4Y= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-620-L51CUMXUOgaWzMV0lMozWg-1; Tue, 05 Aug 2025 02:23:44 -0400 X-MC-Unique: L51CUMXUOgaWzMV0lMozWg-1 X-Mimecast-MFC-AGG-ID: L51CUMXUOgaWzMV0lMozWg_1754375023 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (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-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 8D3CD180045C; Tue, 5 Aug 2025 06:23:42 +0000 (UTC) Received: from MiWiFi-R3L-srv.redhat.com (unknown [10.72.112.136]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 9AF5F1956094; Tue, 5 Aug 2025 06:23:36 +0000 (UTC) From: Baoquan He To: linux-mm@kvack.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, Baoquan He Subject: [PATCH 0/4] mm/kasan: make kasan=on|off work for all three modes Date: Tue, 5 Aug 2025 14:23:29 +0800 Message-ID: <20250805062333.121553-1-bhe@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-type: text/plain Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 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. Test: ===== I only took test on x86_64 for generic mode, and on arm64 for generic, sw_tags and hw_tags mode. All of them works well. However when I tested sw_tags on a HPE apollo arm64 machine, it always breaks kernel with a KASAN bug. Even w/o this patchset applied, the bug can always be seen too. "BUG: KASAN: invalid-access in pcpu_alloc_noprof+0x42c/0x9a8" I haven't got root cause of the bug, will report the bug later in another thread. ==== Baoquan He (4): mm/kasan: add conditional checks in functions to return directly if kasan is disabled mm/kasan: move kasan= code to common place mm/kasan: don't initialize kasan if it's disabled mm/kasan: make kasan=on|off take effect for all three modes 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/mm/kasan_init.c | 6 +++++ include/linux/kasan-enabled.h | 11 ++------ mm/kasan/common.c | 27 ++++++++++++++++++++ mm/kasan/generic.c | 20 +++++++++++++-- mm/kasan/hw_tags.c | 35 ++------------------------ mm/kasan/init.c | 6 +++++ mm/kasan/quarantine.c | 3 +++ mm/kasan/shadow.c | 23 ++++++++++++++++- mm/kasan/sw_tags.c | 9 +++++++ 18 files changed, 150 insertions(+), 46 deletions(-) -- 2.41.0