From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932112AbcEXH7F (ORCPT ); Tue, 24 May 2016 03:59:05 -0400 Received: from mga02.intel.com ([134.134.136.20]:49226 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753249AbcEXH7D (ORCPT ); Tue, 24 May 2016 03:59:03 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.26,359,1459839600"; d="scan'208";a="973297839" Date: Tue, 24 May 2016 10:58:57 +0300 From: Mika Westerberg To: Bjorn Helgaas Cc: Valdis Kletnieks , Lukas Wunner , "Rafael J . Wysocki" , linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org Subject: Re: [PATCH] PCI: pcie: Call pm_runtime_no_callbacks() after device is registered Message-ID: <20160524075857.GC1712@lahna.fi.intel.com> References: <14501.1463692755@turing-police.cc.vt.edu> <1463991115-64820-1-git-send-email-mika.westerberg@linux.intel.com> <20160523195500.GA24375@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160523195500.GA24375@localhost> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.6.1 (2016-04-27) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, May 23, 2016 at 02:55:00PM -0500, Bjorn Helgaas wrote: > On Mon, May 23, 2016 at 11:11:55AM +0300, Mika Westerberg wrote: > > Commit 0195d2813547 ("PCI: Add runtime PM support for PCIe ports") added > > call to pm_runtime_no_callbacks() for each port service device to prevent > > them exposing unnecessary runtime PM sysfs files. However, that function > > tries to acquire dev->power.lock which is not yet initialized. > > > > This triggers following splat: > > > > BUG: spinlock bad magic on CPU#0, swapper/0/1 > > lock: 0xffff8801be2aa8e8, .magic: 00000000, .owner: /-1, .owner_cpu: 0 > > CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.6.0+ #820 > > 0000000000000000 ffff8801beb97be0 ffffffff812cf42d 0000000000000000 > > ffff8801be2aa8e8 ffff8801beb97c00 ffffffff8109ee58 ffff8801be2aa8e8 > > ffff8801be2aa8e8 ffff8801beb97c30 ffffffff8109efd9 ffff8801be2aa8e8 > > Call Trace: > > [] dump_stack+0x4f/0x72 > > [] spin_dump+0x78/0xc0 > > [] do_raw_spin_lock+0xf9/0x150 > > [] _raw_spin_lock_irq+0x20/0x30 > > [] pm_runtime_no_callbacks+0x1e/0x40 > > [] pcie_port_device_register+0x1fd/0x4e0 > > [] pcie_portdrv_probe+0x38/0xa0 > > [] local_pci_probe+0x45/0xa0 > > [] ? pci_match_device+0xe0/0x110 > > [] pci_device_probe+0xdb/0x130 > > [] driver_probe_device+0x22c/0x440 > > [] __driver_attach+0xd1/0xf0 > > [] ? driver_probe_device+0x440/0x440 > > [] bus_for_each_dev+0x64/0xa0 > > [] driver_attach+0x1e/0x20 > > [] bus_add_driver+0x1eb/0x280 > > [] ? pcie_port_setup+0x7c/0x7c > > [] driver_register+0x60/0xe0 > > [] __pci_register_driver+0x60/0x70 > > [] pcie_portdrv_init+0x63/0x75 > > [] do_one_initcall+0xab/0x1c0 > > [] kernel_init_freeable+0x153/0x1d9 > > [] kernel_init+0xe/0x100 > > [] ret_from_fork+0x22/0x40 > > [] ? rest_init+0x90/0x90 > > > > Fix this by calling pm_runtime_no_callbacks() after device_register() just > > like other buses, like I2C is doing already. > > > > Reported-by: Valdis Kletnieks > > Tested-by: Valdis Kletnieks > > Suggested-by: Lukas Wunner > > Signed-off-by: Mika Westerberg > > I think this is a bugfix for "PCI: Add runtime PM support for PCIe > ports", so I folded this into that patch since it hasn't been merged > yet. Is that the right place for it? Yes, that's right. Thanks!