From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Mon, 23 May 2016 14:55:00 -0500 From: Bjorn Helgaas To: Mika Westerberg 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: <20160523195500.GA24375@localhost> References: <14501.1463692755@turing-police.cc.vt.edu> <1463991115-64820-1-git-send-email-mika.westerberg@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1463991115-64820-1-git-send-email-mika.westerberg@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: 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? > --- > drivers/pci/pcie/portdrv_core.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c > index 65b1a624826b..97927dfbbf5f 100644 > --- a/drivers/pci/pcie/portdrv_core.c > +++ b/drivers/pci/pcie/portdrv_core.c > @@ -344,7 +344,6 @@ static int pcie_device_init(struct pci_dev *pdev, int service, int irq) > get_descriptor_id(pci_pcie_type(pdev), service)); > device->parent = &pdev->dev; > device_enable_async_suspend(device); > - pm_runtime_no_callbacks(device); > > retval = device_register(device); > if (retval) { > @@ -352,6 +351,8 @@ static int pcie_device_init(struct pci_dev *pdev, int service, int irq) > return retval; > } > > + pm_runtime_no_callbacks(device); > + > return 0; > } > > -- > 2.8.1 >