Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756056AbYLPWVn (ORCPT ); Tue, 16 Dec 2008 17:21:43 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752286AbYLPWVb (ORCPT ); Tue, 16 Dec 2008 17:21:31 -0500 Received: from wf-out-1314.google.com ([209.85.200.170]:30391 "EHLO wf-out-1314.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751671AbYLPWVa (ORCPT ); Tue, 16 Dec 2008 17:21:30 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version :content-type:content-transfer-encoding:content-disposition :references; b=LrAyXQ9EHeKqZJv89/+SrrQOtxd2NxDd+EdBCZHaUu4mA1u1tIYP7yYaqouVUJBB5g AkDCHktq49yrtsoxbYDVEvfxiNQ7KKqSygLtw0kyyubMpvJN63DS37FDsoD6VluI+cGN h2kCeYRAnpw/bCRVuIf73Xit1gIv0p2yLv0iw= Message-ID: Date: Wed, 17 Dec 2008 01:21:29 +0300 From: "Alexey Zaytsev" To: "Ingo Molnar" Subject: Re: linux-next: Tree for December 11 Cc: "Stephen Rothwell" , linux-next@vger.kernel.org, LKML , "Nick Piggin" In-Reply-To: <20081216210834.GM14787@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20081211200459.14d18d7a.sfr@canb.auug.org.au> <20081216210834.GM14787@elte.hu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Dec 17, 2008 at 00:08, Ingo Molnar wrote: >> >> The warning can also be reproduced in qemu, so it was easy to bisect. >> >> commit 7317d7b87edb41a9135e30be1ec3f7ef817c53dd >> Author: Nick Piggin >> Date: Tue Sep 30 20:50:27 2008 +1000 >> >> sched: improve preempt debugging >> >> This patch helped me out with a problem I recently had.... >> >> Basically, when the kernel lock is held, then preempt_count >> underflow does not >> get detected until it is released which may be a long time (and arbitrarily, >> eg at different points it may be rescheduled). If the bkl is released at >> schedule, the resulting output is actually fairly cryptic... >> >> With any other lock that elevates preempt_count, it is illegal to schedule >> under it (which would get found pretty quickly). bkl allows scheduling with >> preempt_count elevated, which makes underflows hard to debug. >> >> Signed-off-by: Ingo Molnar >> >> I understand that not this particular commit is buggy, but at least >> I've got someone to add to the CC. ;) >> >> Also the author's e-mail looks suspicious. > > Suspicious in what way? Does not appear in signed-off-by. > > Ingo > -- 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/