From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.1 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 54C97C433F4 for ; Thu, 30 Aug 2018 17:15:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 12B5A20658 for ; Thu, 30 Aug 2018 17:15:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="hVY7YNen" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 12B5A20658 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727251AbeH3VSZ (ORCPT ); Thu, 30 Aug 2018 17:18:25 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:41118 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725893AbeH3VSY (ORCPT ); Thu, 30 Aug 2018 17:18:24 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=ibAuDr8ktP8kc2VavoK2sMX9glq0IfQtKZyoqsVAfGU=; b=hVY7YNenpj9YIoAl+jQarf0BF gfsl4Kh2FmDudNsRZ0pXAdA7D2PbluQ5/n0/Jg//5PeISvwzBBGMCcu2CPD01Yoxj8LiRiBESYHK7 7J7P86530k2gz4zAq3lNsK0ZHiK5eM+EkZAESdFe07+xbBQlFGrHvF97hHFhA/AlO4axLF1jFYipw f698IvlIIWLPglyrSxbROMC1gXViIx9n7X/AJks/q4QVbfyYQqDJQXr64kXUaZPylRqknt7n/tJLm VkyLUNXsiysL4fTxnolApzf7Gk2zy5kAqSHxpaQPVHVQmRLPA/xg9ufFK1KcFTP9M0VSU1uzKnO7C pOs/+XyRA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1fvQXJ-0002FA-1T; Thu, 30 Aug 2018 17:15:13 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 8A1B92024D73F; Thu, 30 Aug 2018 19:15:10 +0200 (CEST) Date: Thu, 30 Aug 2018 19:15:10 +0200 From: Peter Zijlstra To: Eugeniy Paltsev Cc: "mingo@kernel.org" , "linux-kernel@vger.kernel.org" , "Alexey.Brodkin@synopsys.com" , "Vineet.Gupta1@synopsys.com" , "tglx@linutronix.de" , "linux-snps-arc@lists.infradead.org" , "yamada.masahiro@socionext.com" , "will.deacon@arm.com" , "linux-arm-kernel@lists.infradead.org" , "linux-arch@vger.kernel.org" Subject: Re: Patch "asm-generic/bitops/lock.h: Rewrite using atomic_fetch_" causes kernel crash Message-ID: <20180830171510.GQ24082@hirez.programming.kicks-ass.net> References: <1535567633.4465.23.camel@synopsys.com> <20180830094411.GX24124@hirez.programming.kicks-ass.net> <20180830095148.GB5942@arm.com> <1535629996.4465.44.camel@synopsys.com> <20180830141713.GN24082@hirez.programming.kicks-ass.net> <1535640375.4465.68.camel@synopsys.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1535640375.4465.68.camel@synopsys.com> User-Agent: Mutt/1.10.0 (2018-05-17) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 30, 2018 at 02:46:16PM +0000, Eugeniy Paltsev wrote: > On Thu, 2018-08-30 at 16:17 +0200, Peter Zijlstra wrote: > > On Thu, Aug 30, 2018 at 11:53:17AM +0000, Eugeniy Paltsev wrote: > > > I can see crashes with LLSC enabled in both SMP running on 4 cores > > > and SMP running on 1 core. > > > > So you're running on LL/SC enabled hardware; that would make Will's > > patch irrelevant (although still a good idea for the hardware that does > > care about that spinlocked atomic crud). > > > > Does something like the below cure things? That would confirm the > > suggestion that the change to __clear_bit_unlock() is the curprit. > > I tested it - this doesn't change anything, the problem still reproduces. OK, 'good' :-) > I'll test it with last Will fix. Yes, that missing "bnz 1b" is very very suspect.