[haiku-bugs] Re: [Haiku] #12549: KDL booting hrev49947 x86_gcc2

From: "waddlesplash" <trac@xxxxxxxxxxxx>
Date: Fri, 01 Jan 2016 16:15:28 -0000

#12549: KDL booting hrev49947 x86_gcc2
----------------------------+----------------------------
   Reporter:  kim1963       |      Owner:  waddlesplash
       Type:  bug           |     Status:  assigned
   Priority:  high          |  Milestone:  R1/beta1
  Component:  Drivers/ACPI  |    Version:  R1/Development
Resolution:                |   Keywords:
Blocked By:                |   Blocking:
Has a Patch:  0             |   Platform:  x86
----------------------------+----------------------------

Comment (by waddlesplash):

A friend of mine who knows more about assembly than I do actually spent
some time looking at this. Here's what he sent me:

Here is what I discovered to be true, looking at the backtrace and the

disassembly:

1. In AcpiNsBuildNormalizedPath() %esi is used for the variable

NextNode.

2. In the stack trace %esi=0x656d5f6c looks suspiciously like it is a

pointer loaded after a buffer overrun. The ascii would be 'l_me'

3. It is unlikely that the parameter, Node, is bad, because the caller

used a handle validate routine.

4. When walking the tree, NextNode is loaded from each .Parent in turn.

This means that one of the .Parents is bad.

5. %edi is used for the variable Length. At the time of the stack

trace, it is 0xa. I think that means that it walked up at least two nodes
before it hit the bad one.

6. Inserting a little debugging code right there might help provide a

clue to track down the problem. if (NextNode==0x656d5f6c), then you want
to dump what is at FullPath so far, and then panic. Better yet, start at
Node, and walk forward, dumping each block [Node,sizeof(*Node)].

--
Ticket URL: <https://dev.haiku-os.org/ticket/12549#comment:11>
Haiku <https://dev.haiku-os.org>
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[haiku-bugs] Re: [Haiku] #12549: KDL booting hrev49947 x86_gcc2

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