From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-174.mta1.migadu.com (out-174.mta1.migadu.com [95.215.58.174]) (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 E395433B6F9 for ; Fri, 19 Jun 2026 21:43:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.174 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781905410; cv=none; b=C5E9mtwFUarQBqAePwd41u3esAW0ZdBvdfr2FkCM7Bs87sMdDoyLMwIaMyEO7njeie1IgVyfWLdbIq9clh41OSZaYG66RAoWT7C2ZmV/oc9u6hhq5YL1R/fuR8PNxN8aUXKquG746rHlxAEhV7KBA3WXD03IYVxfHv/HCFTpt6Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781905410; c=relaxed/simple; bh=QUA+LosX10v+Ij4GqBpRxkWHmVwuPC+tYDQpWoWMEHs=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Ft2wKBT7jhudx1megn70XTr1taCWtrFhfK984K7N/Zu7g9/E004wtdjtuby3dEHKo/tiKGBc6DHOFhC7EbkKgSg6cXP9BfiV1/Ea+pHM7X/lHbzyzd0RkKCmG2SSlUEf/JjhUR6U9EspqTUra5Oo1D7Wo+90FqtsrMnSnCLibnk= 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=rpV8hAyv; arc=none smtp.client-ip=95.215.58.174 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="rpV8hAyv" Date: Fri, 19 Jun 2026 23:43:18 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1781905405; 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=AHDhM+VItgHUsK7dJiw+MLd6Yt7jD73Rn04x8AKnG9k=; b=rpV8hAyvwYJVkDDCDe6cDhr3ofKY9gXtHqneB4TMfPE6W9/YuXzUI4vPGY0t7KaHwUgCpn Xj3IZzSDlB9TzkGpnz3Noq6ir0FQTlrAQo+zCGzy0EhThbHsC5kxjQrb2PXG/fGuglLCXH bZ270FHURHAoRZ5L/EEPOFC0N46cbCI= 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: <20260618163856.GAajQfIDh0s31VINiS@fat_crate.local> <20260618180412.GBajQzHB3Rj0SrS1Eo@fat_crate.local> <20260618193409.GFajRIMdiw-2WGJRKN@fat_crate.local> <20260619024814.GIajSt7h4E7GXlsO5U@fat_crate.local> <20260619202421.GAajWlddFHPr1hl7AD@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: <20260619202421.GAajWlddFHPr1hl7AD@fat_crate.local> X-Migadu-Flow: FLOW_OUT On Fri, Jun 19, 2026 at 01:24:21PM -0700, Borislav Petkov wrote: > On Fri, Jun 19, 2026 at 09:57:58AM +0200, Thorsten Blum wrote: > > Are you perhaps appending nokaslr? > > Yes, removed it. Same thing. > > > 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" > > As said, efistub entry point bypassing get_cmdline_acpi_rsdp(): > > ... > -drive if=pflash,format=raw,unit=0,file=/home/boris/kvm/debian/uefi/OVMF_CODE_4M-sid-uefi.fd,readonly=on > -drive if=pflash,format=raw,unit=1,file=/home/boris/kvm/debian/uefi/OVMF_VARS_4M-sid-uefi.fd,readonly=of > ... > > So I can't reproduce it. Right, but that is a different setup, which bypasses get_cmdline_acpi_rsdp() and is not expected to reproduce this bug. Could you please try the exact direct kernel boot reproducer I provided, using defconfig and CONFIG_MEMORY_HOTREMOVE=y? $ qemu-system-x86_64 -nographic -no-reboot -kernel arch/x86/boot/bzImage -append "console=ttyS0 acpi_rsdp=0x0123456789abcdefx" That path reaches get_cmdline_acpi_rsdp() and should crash during early boot without the patch. Thanks.