diff options
| author | James Bottomley <James.Bottomley@suse.de> | 2011-04-22 10:39:59 -0500 |
|---|---|---|
| committer | James Bottomley <James.Bottomley@suse.de> | 2011-04-24 11:02:17 -0500 |
| commit | 86cbfb5607d4b81b1a993ff689bbd2addd5d3a9b (patch) | |
| tree | fbb980129ed8b6ecabfed492f0c53b29280cd06e | |
| parent | 0b8393578c70bc1f09790eeae7d918f38da2e010 (diff) | |
[SCSI] put stricter guards on queue dead checks
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.
Cc: stable@kernel.org
Signed-off-by: James Bottomley <James.Bottomley@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 e44ff64233f..e63912510fb 100644 --- a/drivers/scsi/scsi_sysfs.c +++ b/drivers/scsi/scsi_sysfs.c @@ -322,14 +322,8 @@ 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)); @@ -937,6 +931,12 @@ 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); } |