From 860dc73608a091e0b325218acc2701709d5f221a Mon Sep 17 00:00:00 2001 From: James Bottomley Date: Thu, 19 Nov 2009 17:48:29 -0500 Subject: [SCSI] fix async scan add/remove race resulting in an oops Async scanning introduced a very wide window where the SCSI device is up and running but has not yet been added to sysfs. We delay the adding until all scans have completed to retain the same ordering as sync scanning. This delay in visibility causes an oops if a device is removed before we make it visible because the SCSI removal routines have an inbuilt assumption that if a device is in SDEV_RUNNING state, it must be visible (which is not necessarily true in the async scanning case). Fix this by introducing an additional is_visible flag which we can use to condition the tear down so we do the right thing for running but not yet made visible. Reported-by: Alexey Kuznetsov Signed-off-by: James Bottomley --- drivers/scsi/scsi_sysfs.c | 63 ++++++++++++++++++++--------------------------- 1 file changed, 27 insertions(+), 36 deletions(-) (limited to 'drivers/scsi/scsi_sysfs.c') diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c index 5c7eb63a19d..392d8db3390 100644 --- a/drivers/scsi/scsi_sysfs.c +++ b/drivers/scsi/scsi_sysfs.c @@ -854,82 +854,73 @@ int scsi_sysfs_add_sdev(struct scsi_device *sdev) transport_configure_device(&starget->dev); error = device_add(&sdev->sdev_gendev); if (error) { - put_device(sdev->sdev_gendev.parent); printk(KERN_INFO "error 1\n"); - return error; + goto out_remove; } error = device_add(&sdev->sdev_dev); if (error) { printk(KERN_INFO "error 2\n"); - goto clean_device; + device_del(&sdev->sdev_gendev); + goto out_remove; } + transport_add_device(&sdev->sdev_gendev); + sdev->is_visible = 1; /* create queue files, which may be writable, depending on the host */ if (sdev->host->hostt->change_queue_depth) error = device_create_file(&sdev->sdev_gendev, &sdev_attr_queue_depth_rw); else error = device_create_file(&sdev->sdev_gendev, &dev_attr_queue_depth); - if (error) { - __scsi_remove_device(sdev); - goto out; - } + if (error) + goto out_remove; + if (sdev->host->hostt->change_queue_type) error = device_create_file(&sdev->sdev_gendev, &sdev_attr_queue_type_rw); else error = device_create_file(&sdev->sdev_gendev, &dev_attr_queue_type); - if (error) { - __scsi_remove_device(sdev); - goto out; - } + if (error) + goto out_remove; error = bsg_register_queue(rq, &sdev->sdev_gendev, NULL, NULL); if (error) + /* we're treating error on bsg register as non-fatal, + * so pretend nothing went wrong */ sdev_printk(KERN_INFO, sdev, "Failed to register bsg queue, errno=%d\n", error); - /* we're treating error on bsg register as non-fatal, so pretend - * nothing went wrong */ - error = 0; - /* add additional host specific attributes */ if (sdev->host->hostt->sdev_attrs) { for (i = 0; sdev->host->hostt->sdev_attrs[i]; i++) { error = device_create_file(&sdev->sdev_gendev, sdev->host->hostt->sdev_attrs[i]); - if (error) { - __scsi_remove_device(sdev); - goto out; - } + if (error) + goto out_remove; } } - transport_add_device(&sdev->sdev_gendev); - out: - return error; - - clean_device: - scsi_device_set_state(sdev, SDEV_CANCEL); - - device_del(&sdev->sdev_gendev); - transport_destroy_device(&sdev->sdev_gendev); - put_device(&sdev->sdev_dev); - put_device(&sdev->sdev_gendev); + return 0; + out_remove: + __scsi_remove_device(sdev); return error; + } void __scsi_remove_device(struct scsi_device *sdev) { struct device *dev = &sdev->sdev_gendev; - if (scsi_device_set_state(sdev, SDEV_CANCEL) != 0) - return; + if (sdev->is_visible) { + if (scsi_device_set_state(sdev, SDEV_CANCEL) != 0) + return; - bsg_unregister_queue(sdev->request_queue); - device_unregister(&sdev->sdev_dev); - transport_remove_device(dev); - device_del(dev); + bsg_unregister_queue(sdev->request_queue); + device_unregister(&sdev->sdev_dev); + transport_remove_device(dev); + device_del(dev); + } else + put_device(&sdev->sdev_dev); scsi_device_set_state(sdev, SDEV_DEL); if (sdev->host->hostt->slave_destroy) sdev->host->hostt->slave_destroy(sdev); -- cgit