Re: [2.6.14-rc1] sym scsi boot hang

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

Alan Stern wrote:
> On Wed, 14 Sep 2005, Anton Blanchard wrote:
> 
> 
>>Hi,
>>
>>
>>>If that's the cause, it's probably a double down of the host scan
>>>semaphore somewhere in the code.  alt-sysrq-t should work in this case,
>>>can you get a stack trace of the blocked process?
>>
>>It appears to be this patch:
>>
>>  [SCSI] SCSI core: fix leakage of scsi_cmnd's
>>
>>  From:         Alan Stern <stern@rowland.harvard.edu>
> 
> 
>>And in particular it looks like the scsi_unprep_request in
>>scsi_queue_insert is causing it. The following patch fixes the boot
>>problems on the vscsi machine:
> 
> 
> In general the scsi_unprep_request routine is correct and needs to be
> there.  The one part that might be questionable is the assignment to
> req->special.  It may turn out that the real solution is to have
> scsi_execute set req->special to NULL; I assumed it would be NULL already
> but perhaps I was wrong.

I think we have scsi_execute and friends setting REQ_SPECIAL. This is 
could cause a problem becuase it does not have a scsi_request.