Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752207AbXAZWFh (ORCPT ); Fri, 26 Jan 2007 17:05:37 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752208AbXAZWFg (ORCPT ); Fri, 26 Jan 2007 17:05:36 -0500 Received: from nf-out-0910.google.com ([64.233.182.189]:55911 "EHLO nf-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752206AbXAZWFg (ORCPT ); Fri, 26 Jan 2007 17:05:36 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=fup/hdsAjwmqxuY0NNnKuvWREY3KB38p5vw0ZeGOLmuH4iNECkNsZj4vFw2zmQP3xYePN2OW5ZTn3l3pVXO/uRWOSAQgDj4NTPIM6GX6je4P6acUA9i7yGPVTqVqXYNsR3A2zxfdlBoXnL9QHh4IXOQ2F+Ns+Pk2ldaQZtvTP8k= Message-ID: Date: Fri, 26 Jan 2007 14:05:31 -0800 From: "Michael K. Edwards" To: "Segher Boessenkool" Subject: Re: kernel + gcc 4.1 = several problems Cc: "Denis Vlasenko" , akpm@osdl.org, "Albert Cahalan" , linux-kernel@vger.kernel.org, s0348365@sms.ed.ac.uk, "Linus Torvalds" , bunk@stusta.de, mikpe@it.uu.se In-Reply-To: <11fc5e81b224467e25caaefb66ba82e7@kernel.crashing.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <787b0d920701032311l2c37c248s3a97daf111fe88f3@mail.gmail.com> <787b0d920701040904i553e521fsb290acf5059f0b62@mail.gmail.com> <200701070525.45974.vda.linux@googlemail.com> <11fc5e81b224467e25caaefb66ba82e7@kernel.crashing.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1250 Lines: 24 ALSA + GCC 4.1.1 + -Os is known to be a bad combination on some arches; see http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27363 . (I tripped over it on an ARM target, but my limited understanding of GCC internals does not allow me to conclude that it is ARM-specific.) A patch claiming to fix the bug was integrated into the 4.1 branch, but my tests with a recent (20070115) gcc-4.1 snapshot indicate that it has regressed again. You might also check /proc/cpu/alignment; we have seen the alignment fixup code trigger for alignment errors in both kernel and userspace. The default appears to be to IGNORE alignment traps from userspace, which results in bogus data and potentially a wacky series of system calls, which could conceivably trigger an oops. I am told that echo 2 > /proc/cpu/alignment activates the kernel alignment fixup code, and that 3 turns on some sort of logging in addition to the fixup (haven't pursued this myself). No idea whether this is relevant to your CPU. Cheers, - Michael - 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/