From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.alien8.de (mail.alien8.de [65.109.113.108]) (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 B12F21420DF; Mon, 8 Jul 2024 16:49:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=65.109.113.108 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720457345; cv=none; b=LLD+hkDPkzaE8xqZtacN5SzTeIB2zYAD2Sm/43Wik6YmoB9sFmZbK4+YF2vCxsp9AoSBQ0GeChB8gYgpmHEQBr5tyzl/7V218L0aOH+KubzCwVd17/dbMBafjRtrL7uZ14vVsUUnU5R8FT3HcJEutBMLZ+OkkYWNU9RgPmjcffI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720457345; c=relaxed/simple; bh=dn2Naz7DgHKdIPlqUUXdQML8v/8YmmXJzyHEKsgUUkk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Dw8AuZHf9QjCzvpXc17tFjWhwYVEjPiO5AFDvaOLM0cthMCbA545apz1JFZLWkJkl1NL1Ys/MxDZCKYUusBZArXPT4fT9upSaXSJ58GY+1HGFf1Rcm17RDIWsENCEB8uCsthWDz9n7tuGDVnfSY7RIwXr/7ae3NuqhoUa8J/1zk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=alien8.de; spf=pass smtp.mailfrom=alien8.de; dkim=pass (4096-bit key) header.d=alien8.de header.i=@alien8.de header.b=VMNZywL6; arc=none smtp.client-ip=65.109.113.108 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=alien8.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=alien8.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (4096-bit key) header.d=alien8.de header.i=@alien8.de header.b="VMNZywL6" Received: from localhost (localhost.localdomain [127.0.0.1]) by mail.alien8.de (SuperMail on ZX Spectrum 128k) with ESMTP id 8875540E019D; Mon, 8 Jul 2024 16:49:01 +0000 (UTC) X-Virus-Scanned: Debian amavisd-new at mail.alien8.de Authentication-Results: mail.alien8.de (amavisd-new); dkim=pass (4096-bit key) header.d=alien8.de Received: from mail.alien8.de ([127.0.0.1]) by localhost (mail.alien8.de [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id QCR0pN8wUZMS; Mon, 8 Jul 2024 16:48:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=alien8; t=1720457338; bh=4SpgDKEgGt9WxI4KKGDZv5tcCTEy2R9UvSKhwxPW1Fs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=VMNZywL6m9FSPyMeeByybJqpDsMCXpjX5av9p8sr2TjwNHDV1dv3LQyEUSvMrJoQq hF8YkjB0AfXMCPjEfF8tTPZygKs6QdnRfwgqHleqTUmON5B1HN2etgcPUHYBKgCmma k5054tLqmNq6IYlYnS9odXv+jbaIPBV7/tO8SOSLvO211zv0EWGGc7F8LrIj5Y663I mlsSrvfVUsDy2C5IjdoAgxdQs2Lsw5cIrqUDLS9KoxOIbhNV87Q0DJsVFnzycAvHMZ AzXhhaJ2QEAqJlunfOIa3Fu5rOEU35t01E6rgOtqE6toQpu7iXuj//fmmN7QRlhJdk vbrNiug8rVgBKaeQvW6G0cWHS4BA893t8d1RELv6QUKG2qlkT54W3jia8HeFXNWd5p BmskGSrhqb87veKMUFOxk1nxasS/Ns1+ZJtsh8o/kUmI4WGPvpwy54FdnWLRqfu7T8 +eUvKs7ABnfvL3VOXDhaAySBuZEhr/CC6+R+dpXHdyGJgZJbPFuTcm9hVNUKD3qPD6 hrlHIoogIbHRqgJyZ01w0WwGQUl1l3+6zN5jBYH4C5wvcJsCZRQ3Ld5J5PTaDeyBUc +1TsRXh06/8RsqhCLJvt29q5blOU+B3sN4osw33IDB3Qdby1YBnLDAjTCR/C2CztB3 umocZt5irpesD90/uHlRJ1Z4= Received: from zn.tnic (p5de8ee85.dip0.t-ipconnect.de [93.232.238.133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature ECDSA (P-256) server-digest SHA256) (No client certificate requested) by mail.alien8.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id EE9B840E0177; Mon, 8 Jul 2024 16:48:51 +0000 (UTC) Date: Mon, 8 Jul 2024 18:48:46 +0200 From: Borislav Petkov To: linux-kernel@vger.kernel.org Cc: linux-tip-commits@vger.kernel.org, kernel test robot , Alexandre Chartre , Josh Poimboeuf , x86@kernel.org Subject: Re: [tip: objtool/core] objtool/x86: objtool can confuse memory and stack access Message-ID: <20240708164846.GFZowYbmQpBu2Y4GeL@fat_crate.local> References: <20240620144747.2524805-1-alexandre.chartre@oracle.com> <172043936454.2215.16620277258416300859.tip-bot2@tip-bot2> 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=utf-8 Content-Disposition: inline In-Reply-To: <172043936454.2215.16620277258416300859.tip-bot2@tip-bot2> On Mon, Jul 08, 2024 at 11:49:24AM -0000, tip-bot2 for Alexandre Chartre wrote: > 4c 8b 24 25 e0 ff ff mov 0xffffffffffffffe0,%r12 Right, this is missing a "ff" which is the 4th byte of a disp32. I.e., ModRM=0, SIB=5 simply means that what follows is a disp32 field: REX: 0x4c { 4 [w]: 1 [r]: 1 [x]: 0 [b]: 0 } Opcode: 0x8b ModRM: 0x24 [mod:0b][.R:1b,reg:1100b][.B:0b,r/m:100b] register-indirect mode, offset 0 SIB: 0x25 [.B:0b,base:101b][.X:0b,idx:100b][scale: 0] MOV Gv,Ev; MOV reg{16,32,64} reg/mem{16,32,64} 0: 4c 8b 24 25 e0 ff ff mov 0xffffffffffffffe0,%r12 7: ff -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette