Re: [2.6.14-rc1] sym scsi boot hang

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

Mike Christie wrote:
> 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.
> 

well now actually it won't becuase sc_request should be null for those 
scsi_execute block pc commands I think.