From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> 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: [<ffffffff817daab1>] dump_stack+0x45/0x56 [<ffffffff810436b8>] warn_slowpath_common+0x78/0xa0 [<ffffffff81043727>] warn_slowpath_fmt+0x47/0x50 [<ffffffff811ad319>] ? sysfs_get_dirent_ns+0x49/0x70 [<ffffffff811ae526>] sysfs_remove_group+0xc6/0xd0 [<ffffffff81432f7e>] dpm_sysfs_remove+0x3e/0x50 [<ffffffff8142a0d0>] device_del+0x40/0x1b0 [<ffffffff8142a24d>] device_unregister+0xd/0x20 [<ffffffff8144131a>] scsi_remove_host+0xba/0x110 [<ffffffff8145f526>] ata_host_detach+0xc6/0x100 [<ffffffff8145f578>] ata_pci_remove_one+0x18/0x20 [<ffffffff812e8f48>] pci_device_remove+0x28/0x60 [<ffffffff8142d854>] __device_release_driver+0x64/0xd0 [<ffffffff8142d8de>] device_release_driver+0x1e/0x30 [<ffffffff8142d257>] bus_remove_device+0xf7/0x140 [<ffffffff8142a1b1>] device_del+0x121/0x1b0 [<ffffffff812e43d4>] pci_stop_bus_device+0x94/0xa0 [<ffffffff812e437b>] pci_stop_bus_device+0x3b/0xa0 [<ffffffff812e437b>] pci_stop_bus_device+0x3b/0xa0 [<ffffffff812e44dd>] pci_stop_and_remove_bus_device+0xd/0x20 [<ffffffff812fc743>] trim_stale_devices+0x73/0xe0 [<ffffffff812fc78b>] trim_stale_devices+0xbb/0xe0 [<ffffffff812fc78b>] trim_stale_devices+0xbb/0xe0 [<ffffffff812fcb6e>] acpiphp_check_bridge+0x7e/0xd0 [<ffffffff812fd90d>] hotplug_event+0xcd/0x160 [<ffffffff812fd9c5>] hotplug_event_work+0x25/0x60 [<ffffffff81316749>] acpi_hotplug_work_fn+0x17/0x22 [<ffffffff8105cf3a>] process_one_work+0x17a/0x430 [<ffffffff8105db29>] worker_thread+0x119/0x390 [<ffffffff8105da10>] ? manage_workers.isra.25+0x2a0/0x2a0 [<ffffffff81063a5d>] kthread+0xcd/0xf0 [<ffffffff81063990>] ? kthread_create_on_node+0x180/0x180 [<ffffffff817eb33c>] ret_from_fork+0x7c/0xb0 [<ffffffff81063990>] ? 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 <mika.westerberg@xxxxxxxxxxxxxxx> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> --- 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); } /** -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
