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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 203FCC12002 for ; Fri, 16 Jul 2021 09:32:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F102461400 for ; Fri, 16 Jul 2021 09:32:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233364AbhGPJf0 (ORCPT ); Fri, 16 Jul 2021 05:35:26 -0400 Received: from mga12.intel.com ([192.55.52.136]:13721 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232617AbhGPJfX (ORCPT ); Fri, 16 Jul 2021 05:35:23 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10046"; a="190385471" X-IronPort-AV: E=Sophos;i="5.84,244,1620716400"; d="scan'208";a="190385471" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Jul 2021 02:32:28 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.84,244,1620716400"; d="scan'208";a="573616163" Received: from kuha.fi.intel.com ([10.237.72.162]) by fmsmga001.fm.intel.com with SMTP; 16 Jul 2021 02:32:15 -0700 Received: by kuha.fi.intel.com (sSMTP sendmail emulation); Fri, 16 Jul 2021 12:32:14 +0300 Date: Fri, 16 Jul 2021 12:32:14 +0300 From: Heikki Krogerus To: laurentiu.tudor@nxp.com Cc: andriy.shevchenko@linux.intel.com, gregkh@linuxfoundation.org, rafael@kernel.org, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, jon@solid-run.com Subject: Re: [RFC PATCH] software node: balance refcount for managed sw nodes Message-ID: References: <20210716081711.7638-1-laurentiu.tudor@nxp.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210716081711.7638-1-laurentiu.tudor@nxp.com> Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org Fri, Jul 16, 2021 at 11:17:11AM +0300, laurentiu.tudor@nxp.com kirjoitti: > From: Laurentiu Tudor > > software_node_notify(), on KOBJ_REMOVE drops the refcount twice on managed > software nodes, thus leading to underflow errors. Balance the refcount by > bumping it in the device_create_managed_software_node() function. > > The error [1] was encountered after adding a .shutdown() op to our > fsl-mc-bus driver. > > [1] > pc : refcount_warn_saturate+0xf8/0x150 > lr : refcount_warn_saturate+0xf8/0x150 > sp : ffff80001009b920 > x29: ffff80001009b920 x28: ffff1a2420318000 x27: 0000000000000000 > x26: ffffccac15e7a038 x25: 0000000000000008 x24: ffffccac168e0030 > x23: ffff1a2428a82000 x22: 0000000000080000 x21: ffff1a24287b5000 > x20: 0000000000000001 x19: ffff1a24261f4400 x18: ffffffffffffffff > x17: 6f72645f726f7272 x16: 0000000000000000 x15: ffff80009009b607 > x14: 0000000000000000 x13: ffffccac16602670 x12: 0000000000000a17 > x11: 000000000000035d x10: ffffccac16602670 x9 : ffffccac16602670 > x8 : 00000000ffffefff x7 : ffffccac1665a670 x6 : ffffccac1665a670 > x5 : 0000000000000000 x4 : 0000000000000000 x3 : 00000000ffffffff > x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff1a2420318000 > Call trace: > refcount_warn_saturate+0xf8/0x150 > kobject_put+0x10c/0x120 > software_node_notify+0xd8/0x140 > device_platform_notify+0x4c/0xb4 > device_del+0x188/0x424 > fsl_mc_device_remove+0x2c/0x4c > rebofind sp.c__fsl_mc_device_remove+0x14/0x2c > device_for_each_child+0x5c/0xac > dprc_remove+0x9c/0xc0 > fsl_mc_driver_remove+0x28/0x64 > __device_release_driver+0x188/0x22c > device_release_driver+0x30/0x50 > bus_remove_device+0x128/0x134 > device_del+0x16c/0x424 > fsl_mc_bus_remove+0x8c/0x114 > fsl_mc_bus_shutdown+0x14/0x20 > platform_shutdown+0x28/0x40 > device_shutdown+0x15c/0x330 > __do_sys_reboot+0x218/0x2a0 > __arm64_sys_reboot+0x28/0x34 > invoke_syscall+0x48/0x114 > el0_svc_common+0x40/0xdc > do_el0_svc+0x2c/0x94 > el0_svc+0x2c/0x54 > el0t_64_sync_handler+0xa8/0x12c > el0t_64_sync+0x198/0x19c > ---[ end trace 32eb1c71c7d86821 ]--- > > Reported-by: Jon Nettleton > Signed-off-by: Laurentiu Tudor > --- > drivers/base/swnode.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/base/swnode.c b/drivers/base/swnode.c > index d1f1a8240120..907616ca487f 100644 > --- a/drivers/base/swnode.c > +++ b/drivers/base/swnode.c > @@ -1113,6 +1113,8 @@ int device_create_managed_software_node(struct device *dev, > to_swnode(fwnode)->managed = true; > set_secondary_fwnode(dev, fwnode); > > + kobject_get(&to_swnode(fwnode)->kobj); > + > return 0; > } > EXPORT_SYMBOL_GPL(device_create_managed_software_node); We can't increment the refcount uncoditionally like that. Would this work instead: diff --git a/drivers/base/swnode.c b/drivers/base/swnode.c index d1f1a82401207..bdb50a06c82ae 100644 --- a/drivers/base/swnode.c +++ b/drivers/base/swnode.c @@ -1113,6 +1113,9 @@ int device_create_managed_software_node(struct device *dev, to_swnode(fwnode)->managed = true; set_secondary_fwnode(dev, fwnode); + if (device_is_registered(dev)) + software_node_notify(dev, KOBJ_ADD); + return 0; } EXPORT_SYMBOL_GPL(device_create_managed_software_node); thanks, -- heikki