From bf2cf3baa20b0a6cd2d08707ef05dc0e992a8aa0 Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Fri, 18 Sep 2015 17:23:42 -0700 Subject: [PATCH] scsi: Fix a bdi reregistration race Unregister and reregister BDI devices in the proper order. This patch avoids that the following kernel warning can get triggered: WARNING: CPU: 7 PID: 203 at fs/sysfs/dir.c:31 sysfs_warn_dup+0x68/0x80() sysfs: cannot create duplicate filename '/devices/virtual/bdi/8:32' Workqueue: events_unbound async_run_entry_fn Call Trace: [] dump_stack+0x4c/0x65 [] warn_slowpath_common+0x8a/0xc0 [] warn_slowpath_fmt+0x46/0x50 [] sysfs_warn_dup+0x68/0x80 [] sysfs_create_dir_ns+0x7e/0x90 [] kobject_add_internal+0xa8/0x320 [] kobject_add+0x60/0xb0 [] device_add+0x107/0x5e0 [] device_create_groups_vargs+0xd8/0x100 [] device_create_vargs+0x1c/0x20 [] bdi_register+0x63/0x2a0 [] bdi_register_dev+0x27/0x30 [] add_disk+0x1a9/0x4e0 [] sd_probe_async+0x119/0x1d0 [sd_mod] [] async_run_entry_fn+0x4a/0x140 [] process_one_work+0x1d8/0x7c0 [] worker_thread+0x114/0x460 [] kthread+0xf8/0x110 [] ret_from_fork+0x3f/0x70 See also patch "block: destroy bdi before blockdev is unregistered" (commit ID 6cd18e711dd8). Signed-off-by: Bart Van Assche Reviewed-by: Hannes Reinecke Cc: Signed-off-by: James Bottomley --- drivers/scsi/scsi_sysfs.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c index d3b34d871f4c..0efc21d271b4 100644 --- a/drivers/scsi/scsi_sysfs.c +++ b/drivers/scsi/scsi_sysfs.c @@ -1084,9 +1084,7 @@ void __scsi_remove_device(struct scsi_device *sdev) device_unregister(&sdev->sdev_dev); transport_remove_device(dev); scsi_dh_remove_device(sdev); - device_del(dev); - } else - put_device(&sdev->sdev_dev); + } /* * Stop accepting new requests and wait until all queuecommand() and @@ -1097,6 +1095,16 @@ void __scsi_remove_device(struct scsi_device *sdev) blk_cleanup_queue(sdev->request_queue); cancel_work_sync(&sdev->requeue_work); + /* + * Remove the device after blk_cleanup_queue() has been called such + * a possible bdi_register() call with the same name occurs after + * blk_cleanup_queue() has called bdi_destroy(). + */ + if (sdev->is_visible) + device_del(dev); + else + put_device(&sdev->sdev_dev); + if (sdev->host->hostt->slave_destroy) sdev->host->hostt->slave_destroy(sdev); transport_destroy_device(dev); -- 2.20.1