From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mailout2.samsung.com ([203.254.224.25]:43130 "EHLO mailout2.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751269Ab3K0EeE (ORCPT ); Tue, 26 Nov 2013 23:34:04 -0500 From: Jingoo Han To: "'Rafael J. Wysocki'" , 'Tejun Heo' Cc: 'Mika Westerberg' , 'Greg Kroah-Hartman' , 'Bjorn Helgaas' , linux-kernel@vger.kernel.org, "'James E.J. Bottomley'" , linux-ide@vger.kernel.org, 'Linux PCI' , 'Jingoo Han' References: <1384866598-19716-1-git-send-email-mika.westerberg@linux.intel.com> <3805095.rqdZNnA0Ng@vostro.rjw.lan> <20131125101154.GS2281@intel.com> <9509557.LMLHG8ie3T@vostro.rjw.lan> In-reply-to: <9509557.LMLHG8ie3T@vostro.rjw.lan> Subject: Re: [PATCH] ATA: Fix port removal ordering Date: Wed, 27 Nov 2013 13:34:00 +0900 Message-id: <000001ceeb29$e4d27f70$ae777e50$%han@samsung.com> MIME-version: 1.0 Content-type: text/plain; charset=utf-8 Sender: linux-pci-owner@vger.kernel.org List-ID: On Monday, November 25, 2013 9:19 PM, Rafael J. Wysocki wrote: > > From: Rafael J. Wysocki > > After commit bcdde7e221a8 (sysfs: make __sysfs_remove_dir() recursive) > Mika Westerberg sees traces analogous to the one below in Thunderbolt > hot-remove testing: > > WARNING: CPU: 0 PID: 4 at fs/sysfs/group.c:214 sysfs_remove_group+0xc6/0xd0() > sysfs group ffffffff81c6f1e0 not found for kobject 'host7' > Modules linked in: > CPU: 0 PID: 4 Comm: kworker/0:0 Not tainted 3.12.0+ #13 > Hardware name: /D33217CK, BIOS GKPPT10H.86A.0042.2013.0422.1439 04/22/2013 > Workqueue: kacpi_hotplug acpi_hotplug_work_fn > 0000000000000009 ffff8801002459b0 ffffffff817daab1 ffff8801002459f8 > ffff8801002459e8 ffffffff810436b8 0000000000000000 ffffffff81c6f1e0 > ffff88006d440358 ffff88006d440188 ffff88006e8b4c28 ffff880100245a48 > Call Trace: > [] dump_stack+0x45/0x56 > [] warn_slowpath_common+0x78/0xa0 > [] warn_slowpath_fmt+0x47/0x50 > [] ? sysfs_get_dirent_ns+0x49/0x70 > [] sysfs_remove_group+0xc6/0xd0 > [] dpm_sysfs_remove+0x3e/0x50 > [] device_del+0x40/0x1b0 > [] device_unregister+0xd/0x20 > [] scsi_remove_host+0xba/0x110 > [] ata_host_detach+0xc6/0x100 > [] ata_pci_remove_one+0x18/0x20 > [] pci_device_remove+0x28/0x60 > [] __device_release_driver+0x64/0xd0 > [] device_release_driver+0x1e/0x30 > [] bus_remove_device+0xf7/0x140 > [] device_del+0x121/0x1b0 > [] pci_stop_bus_device+0x94/0xa0 > [] pci_stop_bus_device+0x3b/0xa0 > [] pci_stop_bus_device+0x3b/0xa0 > [] pci_stop_and_remove_bus_device+0xd/0x20 > [] trim_stale_devices+0x73/0xe0 > [] trim_stale_devices+0xbb/0xe0 > [] trim_stale_devices+0xbb/0xe0 > [] acpiphp_check_bridge+0x7e/0xd0 > [] hotplug_event+0xcd/0x160 > [] hotplug_event_work+0x25/0x60 > [] acpi_hotplug_work_fn+0x17/0x22 > [] process_one_work+0x17a/0x430 > [] worker_thread+0x119/0x390 > [] ? manage_workers.isra.25+0x2a0/0x2a0 > [] kthread+0xcd/0xf0 > [] ? kthread_create_on_node+0x180/0x180 > [] ret_from_fork+0x7c/0xb0 > [] ? kthread_create_on_node+0x180/0x180 > > The source of this problem is that SCSI hosts are removed from > ATA ports after calling ata_tport_delete() which removes the > port's sysfs directory, among other things. Now, after commit > bcdde7e221a8, the sysfs directory is removed along with all of > its subdirectories that include the SCSI host's sysfs directory > and its subdirectories at this point. Consequently, when > device_del() is finally called for any child device of the SCSI > host and tries to remove its "power" group (which is already > gone then), it triggers the above warning. > > To make the warnings go away, change the removal ordering in > ata_port_detach() so that the SCSI host is removed from the > port before ata_tport_delete() is called. > > References: https://bugzilla.kernel.org/show_bug.cgi?id=65281 > Reported-and-tested-by: Mika Westerberg > Signed-off-by: Rafael J. Wysocki Tested-by: Jingoo Han I tested this patch on Exynos platform with PCI-SATA card. I checked that the kernel panic is resolved. Thank you. Best regards, Jingoo Han > --- > > Hi, > > This along with https://patchwork.kernel.org/patch/3226081/ makes > all of the warnings observed by Mika go away without the patch at > https://patchwork.kernel.org/patch/3201841/ applied. > > Thanks, > Rafael > > --- > drivers/ata/libata-core.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > Index: linux-pm/drivers/ata/libata-core.c > =================================================================== > --- linux-pm.orig/drivers/ata/libata-core.c > +++ linux-pm/drivers/ata/libata-core.c > @@ -6304,10 +6304,9 @@ static void ata_port_detach(struct ata_p > for (i = 0; i < SATA_PMP_MAX_PORTS; i++) > ata_tlink_delete(&ap->pmp_link[i]); > } > - ata_tport_delete(ap); > - > /* remove the associated SCSI host */ > scsi_remove_host(ap->scsi_host); > + ata_tport_delete(ap); > } > > /** > > --