[ +Cc Tejun ] On Fri, Mar 24, 2017 at 11:44:55AM +0000, John Garry wrote: > To be clear, was this the same test with isci which you initially reported?
Yes, just echo into the PCI device's sysfs remove file and it'll trigger the problem. I did some archeology and it seems as if commit bcdde7e ("sysfs: make __sysfs_remove_dir() recursive") introduced/uncovered this behavior. For reference, here's one of my calltraces (the first of 40!): ------------[ cut here ]------------ WARNING: CPU: 2 PID: 5 at fs/sysfs/group.c:241 sysfs_remove_group+0xc3/0xd0 sysfs group 'power' not found for kobject 'end_device-6:0' CPU: 16 PID: 5884 Comm: repro.sh Not tainted 4.11.0-rc3-libsas+ #504 Call Trace: dump_stack+0x85/0xc2 __warn+0xc6/0xe0 warn_slowpath_fmt+0x4a/0x50 sysfs_remove_group+0xc3/0xd0 dpm_sysfs_remove+0x52/0x60 device_del+0x13c/0x360 ? device_remove_file+0x14/0x20 attribute_container_class_device_del+0x15/0x20 transport_remove_classdev+0x4c/0x60 ? transport_add_class_device+0x40/0x40 attribute_container_device_trigger+0xb3/0xc0 transport_remove_device+0x10/0x20 sas_port_delete+0x12d/0x160 [scsi_transport_sas] sas_deform_port+0x1bf/0x1d0 [libsas] sas_unregister_ports+0x36/0x50 [libsas] sas_unregister_ha+0x1b/0x40 [libsas] isci_unregister+0x2a/0x40 [isci] isci_pci_remove+0x52/0xb0 [isci] ? __pm_runtime_resume+0x56/0x80 pci_device_remove+0x34/0xb0 device_release_driver_internal+0x158/0x210 device_release_driver+0xd/0x10 pci_stop_bus_device+0x85/0x90 pci_stop_and_remove_bus_device_locked+0x15/0x30 remove_store+0x59/0x70 dev_attr_store+0x13/0x20 sysfs_kf_write+0x40/0x50 kernfs_fop_write+0x130/0x1b0 __vfs_write+0x23/0x130 ? rcu_read_lock_sched_held+0x6d/0x80 ? rcu_sync_lockdep_assert+0x2a/0x50 ? __sb_start_write+0xd7/0x1e0 ? vfs_write+0x1a4/0x1f0 vfs_write+0xc6/0x1f0 SyS_write+0x44/0xa0 entry_SYSCALL_64_fastpath+0x23/0xc6 But as I said, I don't belive this is a problem in the SAS transport or the SAS drivers, but a device core or transport class. Byte, Johannes -- Johannes Thumshirn Storage jthumsh...@suse.de +49 911 74053 689 SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: Felix Imendörffer, Jane Smithard, Graham Norton HRB 21284 (AG Nürnberg) Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850