From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 7ACC42F4A1D for ; Tue, 12 Aug 2025 15:10:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755011427; cv=none; b=UAIWFja9e8DNPVkgzKmDvbWdLQ/oFgPJ2FfvUeogq7Ol2q+XMibTnjJbCm9yqPSyRTP+Cyzwkha4PKX3v+Y/ePkqlDF2SaPFCi7qLj0OasmKWBguxmtcmDKhtnwe1NxMH1jdaBobdyl/hNDVn3pYcKp7nE07F7CrDW8SiSEXkO8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755011427; c=relaxed/simple; bh=uXg3JiDSGGOqupxRJv/Ih8srHvr3OKayFvnpfkLJXvM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=lirVkoNz6ipc4VgUyZk4FaJcQa1kmLunK6tHY2zMNDZnBYgCfyfNJXUXxpUxz3pJvkbqWKDDRRBQv53+tjvCTStbh5fvpo0m02mHCBxpzocr3mObBj+uQwR0+A2r/DMT8SqT/RNT7QblGs1NpI6KuhmaOr3euz0lbCXtwzNCqEM= 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=MS+aaoNb; arc=none smtp.client-ip=170.10.129.124 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="MS+aaoNb" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1755011425; 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=PrBFm9KN1k8udVr7PX4kpGMG0V0UIL0fa5o6pxCVKL0=; b=MS+aaoNbp9uqj5PVpncpCRlCsWk+Yhsf4/5fSMWl4WJBgJCftLAVxKxhBYpDTyphdYSBKE TE4efQ7ySS7HCMm7eGpzLFNEq2BkE6eLaVMIrDRsJctCGBXXPMQ8nEi1qhDNmUbd+Q8F14 +9zW3SOk+heY45z8YRhOtpQTzFUAf0E= Received: from mx-prod-mc-06.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-693-SghTwAjnNS-be_4HqIcxxA-1; Tue, 12 Aug 2025 11:10:22 -0400 X-MC-Unique: SghTwAjnNS-be_4HqIcxxA-1 X-Mimecast-MFC-AGG-ID: SghTwAjnNS-be_4HqIcxxA_1755011419 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (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-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id D0E1D1808966; Tue, 12 Aug 2025 15:10:11 +0000 (UTC) Received: from localhost (unknown [10.72.112.156]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 4E3871800290; Tue, 12 Aug 2025 15:10:09 +0000 (UTC) Date: Tue, 12 Aug 2025 23:10:04 +0800 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, 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> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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 3.4.1 on 10.30.177.111 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 ~~~~~~~~~~~~~ s/__ro_after_init/kasan_arg_disabled/ Sorry for typo here. > lines in mm/kasan/common.c. Thanks to Marco.