diff options
| author | James Bottomley <James.Bottomley@suse.de> | 2011-04-22 10:39:59 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2011-05-09 16:04:42 -0700 |
| commit | 1f7d953f4de3f3079b9c83d1a23691d4e8c89650 (patch) | |
| tree | 6fdef4d2d7022a4fd2073ced9cd554bd90b6df79 | |
| parent | 5c20dc7633ed54a3794378695934ec949b2354d5 (diff) | |
put stricter guards on queue dead checks
commit 86cbfb5607d4b81b1a993ff689bbd2addd5d3a9b upstream.
SCSI uses request_queue->queuedata == NULL as a signal that the queue
is dying. We set this state in the sdev release function. However,
this allows a small window where we release the last reference but
haven't quite got to this stage yet and so something will try to take
a reference in scsi_request_fn and oops. It's very rare, but we had a
report here, so we're pushing this as a bug fix
The actual fix is to set request_queue->queuedata to NULL in
scsi_remove_device() before we drop the reference. This causes
correct automatic rejects from scsi_request_fn as people who hold
additional references try to submit work and prevents anything from
getting a new reference to the sdev that way.
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | drivers/scsi/scsi_sysfs.c | 16 |
1 files changed, 8 insertions, 8 deletions
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c index 02f719bd0f8..e6926716443 100644 --- a/drivers/scsi/scsi_sysfs.c +++ b/drivers/scsi/scsi_sysfs.c @@ -318,14 +318,8 @@ static void scsi_device_dev_release_usercontext(struct work_struct *work) kfree(evt); } - if (sdev->request_queue) { - sdev->request_queue->queuedata = NULL; - /* user context needed to free queue */ - scsi_free_queue(sdev->request_queue); - /* temporary expedient, try to catch use of queue lock - * after free of sdev */ - sdev->request_queue = NULL; - } + /* NULL queue means the device can't be used */ + sdev->request_queue = NULL; scsi_target_reap(scsi_target(sdev)); @@ -963,6 +957,12 @@ void __scsi_remove_device(struct scsi_device *sdev) if (sdev->host->hostt->slave_destroy) sdev->host->hostt->slave_destroy(sdev); transport_destroy_device(dev); + + /* cause the request function to reject all I/O requests */ + sdev->request_queue->queuedata = NULL; + + /* Freeing the queue signals to block that we're done */ + scsi_free_queue(sdev->request_queue); put_device(dev); } |