Re: [PATCH] fix NULL-pointer dereference on scsi_run_queue

[Mike Christie <michaelc@cs.wisc.edu>]

On 08/04/2012 03:18 PM, Bart Van Assche wrote:
> On 08/04/12 16:46, Mike Christie wrote:
>> I think we have to have scsi-ml do a get_device when a sdev is added to
>> the starved entry and then do a put_device when it is removed (must do
>> these under the host lock for the starved entry case too). I am not sure
>> if that is just a hack/papering-over of the problem and there are more
>> issues like this.
> 
> That would result in a more complex patch than the patch at the start of
> this thread, isn't it ? Also, IMHO it would help to document which

Yaah, but the original patch in this thread is still racey isn't it?

 		spin_unlock(shost->host_lock);

The sdev/queue could get freed by some other thread when this function
is right here, so the get_device call is now going to try to access
freed memory.


+		/* hold a reference on the device so it doesn't release device */
+		get_device(&sdev->sdev_gendev);