Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262028AbVDEVD2 (ORCPT ); Tue, 5 Apr 2005 17:03:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262025AbVDEVDF (ORCPT ); Tue, 5 Apr 2005 17:03:05 -0400 Received: from fire.osdl.org ([65.172.181.4]:40684 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S262028AbVDEVCR (ORCPT ); Tue, 5 Apr 2005 17:02:17 -0400 Date: Tue, 5 Apr 2005 14:04:09 -0700 (PDT) From: Linus Torvalds To: Ingo Molnar cc: Stas Sergeev , linux-kernel@vger.kernel.org, Andrew Morton , Petr Vandrovec Subject: Re: crash in entry.S restore_all, 2.6.12-rc2, x86, PAGEALLOC In-Reply-To: <20050405204436.GA31523@elte.hu> Message-ID: References: <20050405065544.GA21360@elte.hu> <4252E2C9.9040809@aknet.ru> <4252EA01.7000805@aknet.ru> <20050405204436.GA31523@elte.hu> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 953 Lines: 25 On Tue, 5 Apr 2005, Ingo Molnar wrote: > > esi: 009b63f9 edi: 00000001 ebp: f543a000 esp: f543bfc8 > > i.e. esp & 0xfff was 0xfc8 - while i think it should normally be 0xfc4 > (page boundary minus size of pt_regs == 0 - 0x3c == 0xfc4). So somewhere > we lost 4 bytes of esp? An extra popl, or an addl $4, %esp? But why dont > we crash in that case Normally, esp will be immediately reset by any user-land stuff: we'll forget the old kernel stack entirely, and always re-load esp from the esp0 thing in the TSS. And as long as we stay in kernel land, we'll obviously never touch the esp/xss fields of pt_regs (except in this special case of doing the speculative load of xss), so... Linus - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/