#12172 LOW Not Tri: XO-4 B1 8787 pingd data abort

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Thu Feb 7 23:09:06 EST 2013

#12172: XO-4 B1 8787 pingd data abort
           Reporter:  Quozl                |       Owner:  Quozl        
               Type:  defect               |      Status:  new          
           Priority:  low                  |   Milestone:  Not Triaged  
          Component:  ofw - open firmware  |     Version:  not specified
         Resolution:                       |    Keywords:               
        Next_action:  add to build         |    Verified:  0            
Deployment_affected:                       |   Blockedby:               
           Blocking:                       |  
Changes (by Quozl):

  * next_action:  diagnose => add to build


 Fixed in svn 3537.

 A pause in the dots before the Data Abort was found to be
 ''flush-d$-range'' iterating over available memory.

 The parameter stack values given to the flush specified a virtual address
 of h# 0000.0552, which was the encapsulated packet size of 1362 bytes, the
 ping being for 1300 bytes.

 In the SDHCI instance, dma-len was an address and should not have been,
 and dma-vadr was not an address and should have been, and the io-#blocks
 count was negative.

 This pointed at stack imbalance.  Code was added to implement stack
 cookies and saved values at various points in the call chain.

 The problem was found to be in the ring buffer code, which left an item on
 the stack when the ring buffer was first full.

Ticket URL: <http://dev.laptop.org/ticket/12172#comment:4>
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