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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8A68CC4167B for ; Mon, 7 Nov 2022 16:32:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232396AbiKGQcZ (ORCPT ); Mon, 7 Nov 2022 11:32:25 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56902 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232255AbiKGQcL (ORCPT ); Mon, 7 Nov 2022 11:32:11 -0500 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E16622612F for ; Mon, 7 Nov 2022 08:30:18 -0800 (PST) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 8E0D221BEF; Mon, 7 Nov 2022 16:30:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1667838617; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=G0G+B1FI+BKf60trmrpBtM4TOdviP/AMi7QSrgajnxY=; b=BTo9v/EgI3aiUqd9iYdCjvuDON7F80CE/ezeiPUveyP7INNgclAUERekwrK9x8cO5EjM3b aC1BrvvtBvYjP8GJN3KXj98yBhYPMsCtVQbNRmyd4Xgpgpp35JQdbUyEltzQJ6m0gTPEIg of74ywEbq8ZAlq9O7TMYH77/JxdN194= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1667838617; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=G0G+B1FI+BKf60trmrpBtM4TOdviP/AMi7QSrgajnxY=; b=PK7RCHFOtfp6/i3VgV0LRgDc3OMqg70TdNovuWtuGSVS3jnxgfN5QEQgoXEkFyAHG65E6n 1PrWrdMRuHuFxXDg== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 8030A13AC7; Mon, 7 Nov 2022 16:30:17 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id Zb8/H5kyaWNSYAAAMHmgww (envelope-from ); Mon, 07 Nov 2022 16:30:17 +0000 Received: by quack3.suse.cz (Postfix, from userid 1000) id E16D1A0704; Mon, 7 Nov 2022 17:30:16 +0100 (CET) Date: Mon, 7 Nov 2022 17:30:16 +0100 From: Jan Kara To: Sebastian Andrzej Siewior Cc: Jan Kara , LKML , Thomas Gleixner , Steven Rostedt , Mel Gorman , Peter Zijlstra , Ingo Molnar , Will Deacon , Waiman Long , Catalin Marinas Subject: Re: Crash with PREEMPT_RT on aarch64 machine Message-ID: <20221107163016.cnzhknmdnhajfxdh@quack3> References: <20221103115444.m2rjglbkubydidts@quack3> <20221107135636.biouna36osqc4rik@quack3> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 07-11-22 16:10:34, Sebastian Andrzej Siewior wrote: > + locking, arm64 > > On 2022-11-07 14:56:36 [+0100], Jan Kara wrote: > > > spinlock_t and raw_spinlock_t differ slightly in terms of locking. > > > rt_spin_lock() has the fast path via try_cmpxchg_acquire(). If you > > > enable CONFIG_DEBUG_RT_MUTEXES then you would force the slow path which > > > always acquires the rt_mutex_base::wait_lock (which is a raw_spinlock_t) > > > while the actual lock is modified via cmpxchg. > > > > So I've tried enabling CONFIG_DEBUG_RT_MUTEXES and indeed the corruption > > stops happening as well. So do you suspect some bug in the CPU itself? > > If it is only enabling CONFIG_DEBUG_RT_MUTEXES (and not whole lockdep) > then it looks very suspicious. Just to confirm, CONFIG_DEBUG_RT_MUTEXES is the only thing I've enabled and the list corruption disappeared. Honza -- Jan Kara SUSE Labs, CR