From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-181.mta1.migadu.com (out-181.mta1.migadu.com [95.215.58.181]) (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 2E115EED8 for ; Fri, 19 Jun 2026 07:58:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.181 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781855897; cv=none; b=e3uwQKD764oB0FDqzUBjB0Fr61xFP9Lea42FRyNDxXobdi7782uHf6AKxCTTv/12MpEHFiqtnAh46F/yRf1tPICt9Eczdfsq9rTyYNtT95jpqGGMjfnuhr3JCPGxaMPyaJcczod2KA7BYlAhit8OJ9jgw9E+h7n7ACLVGRjdzsk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781855897; c=relaxed/simple; bh=+Qdw80nh5gnagO0WtTjZ5OohWbffmRo8l2WLAamdjdc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=NySukp+fF59Br9VlZAc4yJthjvtCZYtyvnDISeEOFJuQJ5TNt6DmZQ/XRbd8dnJum0lJXO1YRvywXi7dRXdFrTrMOJDPYrFQblPcJeR/3uIvA11TREUXY+It7Rv/7jrgOuXNseRDsrlj/hwpeBfVsTiCif1fdhycR0UbgNyy46k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=cK/pxlgB; arc=none smtp.client-ip=95.215.58.181 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="cK/pxlgB" Date: Fri, 19 Jun 2026 09:57:58 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1781855894; 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=UjR8AYnlCKKyaWpa47ntUSZvqyyY1uj2O9UUzv6ihf4=; b=cK/pxlgBpYQTIw47sp5AD6TjCcfZguot0sLf/+IogaVxD21P3qQSb1LBjOI1/GRGq/ddtB BpXmytg56WIDoK9n8irZBU/mDutc4qI+Hi9HhF7fegmNexfZD20/5qrFEdasvnjLvKI6No CcGHDYwxWHuejiF+NQcfqizbYJ4nmmU= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Thorsten Blum To: Borislav Petkov Cc: Thomas Gleixner , Ingo Molnar , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , linux-kernel@vger.kernel.org Subject: Re: [PATCH] x86/boot: Reject truncated acpi_rsdp= values Message-ID: References: <20260617130417.36651-4-thorsten.blum@linux.dev> <20260618045400.GCajN56AKctO0qB-sF@fat_crate.local> <20260618163856.GAajQfIDh0s31VINiS@fat_crate.local> <20260618180412.GBajQzHB3Rj0SrS1Eo@fat_crate.local> <20260618193409.GFajRIMdiw-2WGJRKN@fat_crate.local> <20260619024814.GIajSt7h4E7GXlsO5U@fat_crate.local> 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: <20260619024814.GIajSt7h4E7GXlsO5U@fat_crate.local> X-Migadu-Flow: FLOW_OUT On Thu, Jun 18, 2026 at 07:48:14PM -0700, Borislav Petkov wrote: > On Fri, Jun 19, 2026 at 03:00:54AM +0200, Thorsten Blum wrote: > > You can reproduce this with QEMU using the malformed example from > > before: > > > > acpi_rsdp=0x0123456789abcdefx > > I just did: it says > > [ 0.000000] Malformed early option 'acpi_rsdp' > > with latest Linus tree without your patch. > > That's because that comes from setup_acpi_rsdp() which calls kstrtoul(). > > I doubt you even hit get_cmdline_acpi_rsdp() as that's the decompressor legacy > path and modern machines boot through the EFI stub like my guest does... Are you perhaps appending nokaslr? With the latest Linus tree, defconfig, and CONFIG_MEMORY_HOTREMOVE=y, this crashes reproducibly for me, but only when KASLR is not disabled: qemu-system-x86_64 -nographic -no-reboot -kernel arch/x86/boot/bzImage -append "console=ttyS0 acpi_rsdp=0x0123456789abcdefx"