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=-10.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SIGNED_OFF_BY,SPF_PASS,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 D8068C43381 for ; Tue, 19 Mar 2019 11:45:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B2F4620857 for ; Tue, 19 Mar 2019 11:45:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727505AbfCSLpR (ORCPT ); Tue, 19 Mar 2019 07:45:17 -0400 Received: from mga17.intel.com ([192.55.52.151]:64898 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726002AbfCSLpP (ORCPT ); Tue, 19 Mar 2019 07:45:15 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga107.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 19 Mar 2019 04:45:14 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.58,497,1544515200"; d="scan'208";a="156317827" Received: from kuha.fi.intel.com ([10.237.72.189]) by fmsmga001.fm.intel.com with SMTP; 19 Mar 2019 04:45:12 -0700 Received: by kuha.fi.intel.com (sSMTP sendmail emulation); Tue, 19 Mar 2019 13:45:11 +0200 Date: Tue, 19 Mar 2019 13:45:11 +0200 From: Heikki Krogerus To: Marc Zyngier , Greg Kroah-Hartman Cc: Guenter Roeck , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] usb: typec: fusb302: Fix debugfs mutex initialisation Message-ID: <20190319114511.GS7752@kuha.fi.intel.com> References: <20190318174906.10429-1-marc.zyngier@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190318174906.10429-1-marc.zyngier@arm.com> User-Agent: Mutt/1.11.3 (2019-02-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 18, 2019 at 05:49:06PM +0000, Marc Zyngier wrote: > Running a kernel with the fusb302 driver and lockdep enabled > leads to an unpleasant warning: > > [ 4.617477] INFO: trying to register non-static key. > [ 4.617930] the code is fine but needs lockdep annotation. > [ 4.618418] turning off the locking correctness validator. > [ 4.618913] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.1.0-rc1-00007-g3542533f3fc9 #13 > [ 4.619620] Hardware name: rockchip evb_rk3399/evb_rk3399, BIOS 2019.04-rc3-00124-g2feec69fb1 03/15/2019 > [ 4.620454] Call trace: > [ 4.620693] dump_backtrace+0x0/0x138 > [ 4.621028] show_stack+0x24/0x30 > [ 4.621336] dump_stack+0xbc/0x104 > [ 4.621649] register_lock_class+0x594/0x598 > [ 4.622036] __lock_acquire+0x80/0x11b8 > [ 4.622384] lock_acquire+0xdc/0x260 > [ 4.622711] __mutex_lock+0x90/0x8a0 > [ 4.623037] mutex_lock_nested+0x3c/0x50 > [ 4.623394] _fusb302_log+0x88/0x1f0 > [ 4.623721] fusb302_log+0x7c/0xa0 > [ 4.624033] tcpm_init+0x5c/0x190 > [ 4.624336] tcpm_init+0x3c/0x130 > [ 4.624640] tcpm_register_port+0x574/0x878 > [ 4.625019] fusb302_probe+0x2c8/0x590 > > Despite what the message says, the code isn't fine, as it tries to > make use of the fusb302_log facility pretty early. This requires the > logbuffer_lock mutex to be initialised, but that only happens much > later. Boo. > > Hoist the fusb302_debugfs_init call before tcpm_register_port so that > we can enjoy a working mutex. At Guenter's request, also add teardown > of the debugfs facility on the error path. > > Signed-off-by: Marc Zyngier After applying this there was no more "fusb302" debugfs directory, and attempt to unload the fusb302 module dead locked. Also, attempt to reboot caused this to happen on my GDPWin board after applying the patch: BUG: Dentry 0000000012f2a05d{i=149,n=i2c-fusb302} still in use (1) [unmount of sysfs sysfs] WARNING: CPU: 3 PID: 1639 at fs/dcache.c:1529 umount_check.cold.55+0x2e/0x3a Modules linked in: intel_xhci_usb_role_switch roles pi3usb30532 typec i915 intel_gtt intel_cht_int33fe [last unloaded: tcpm] CPU: 3 PID: 1639 Comm: umount Not tainted 5.1.0-rc1-heikki+ #916 Hardware name: Default string Default string/Default string, BIOS 5.11 05/25/2017 RIP: 0010:umount_check.cold.55+0x2e/0x3a ... Note. Your patch has also a conflict with patches from Hans, I think with this one: https://patchwork.kernel.org/patch/10847275/ I can take care of that, but you can also rebase the next version on top of my typec-next branch to solve that problem: https://github.com/krohei/linux/commits/typec-next I think I need to add that to the MAINTAINERS file. thanks, -- heikki