Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754061Ab0DAHur (ORCPT ); Thu, 1 Apr 2010 03:50:47 -0400 Received: from gate.crashing.org ([63.228.1.57]:58969 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752522Ab0DAHuk (ORCPT ); Thu, 1 Apr 2010 03:50:40 -0400 Subject: Re: start_kernel(): bug: interrupts were enabled early From: Benjamin Herrenschmidt To: "H. Peter Anvin" Cc: Andrew Morton , Christoph Lameter , Matthew Wilcox , Yinghai Lu , Rabin Vincent , lkml , penberg@cs.helsinki.fi, linux-arch@vger.kernel.org In-Reply-To: <4BB43CAC.3080102@zytor.com> References: <20100325194100.GA2364@debian> <20100331134048.da4e35a7.akpm@linux-foundation.org> <4BB3B4DB.7040904@kernel.org> <20100331210145.GB32165@parisc-linux.org> <4BB3B8FC.1020608@zytor.com> <20100331211754.GC32165@parisc-linux.org> <20100331215411.GB17715@flint.arm.linux.org.uk> <4BB3C540.9000405@zytor.com> <1270075071.7101.79.camel@pasglop> <20100331154955.54176e5e.akpm@linux-foundation.org> <1270084631.7101.81.camel@pasglop> <20100331182654.d36c87ff.akpm@linux-foundation.org> <4BB43CAC.3080102@zytor.com> Content-Type: text/plain; charset="UTF-8" Date: Thu, 01 Apr 2010 17:50:23 +1100 Message-ID: <1270104623.7101.116.camel@pasglop> Mime-Version: 1.0 X-Mailer: Evolution 2.28.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 757 Lines: 24 On Wed, 2010-03-31 at 23:26 -0700, H. Peter Anvin wrote: > On 03/31/2010 03:26 PM, Andrew Morton wrote: > > > > Not by adding overhead to every single down_read()/down_write() just to > > fix a once-off startup problem - that's taking laziness way too far. > > > > How much overhead is this on non-x86 architectures (keep in mind x86 > doesn't use this?) None on powerpc, we use atomic ops and don't disable IRQs. BTW. The same problem used to happen with mutex debug. Was this ever fixed ? Cheers, Ben. -- 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/