RR 6313816: SA: jstack -m fails on Win32 : UnalignedAddressException

[Kevin Walls]

Thanks Poonam!

On 16/05/13 02:26, Poonam Bajaj wrote:
> Hi Kevin,
>
> The changes look good.
>
> Thanks,
> Poonam
>
> On 5/7/2013 5:36 PM, Kevin Walls wrote:
>> Hi -
>>
>> I'd like to get another review from an openjdk user/reviewer/...
>>
>> Thanks
>> Kevin
>>
>>
>> On 03/05/13 09:32, Kevin Walls wrote:
>>> Thanks Staffan, thanks Peter!
>>>
>>>
>>> On 02/05/13 14:11, Peter Allwin wrote:
>>>> Hi Kevin,
>>>>
>>>> Looks good!
>>>>
>>>> I've been looking into improving the quality of native stack traces 
>>>> on Windows using IDebugControl::GetStackTrace. This has the 
>>>> advantage of handling some FPO frames on x86 (a common source of 
>>>> these exceptions), as well as supporting AMD64 (walking the stack 
>>>> using RBP does not work at all on Windows/X64). There are still 
>>>> some issues to iron out before this change is ready, but your fix 
>>>> is a good start to what I'd like to accomplish.
>>>>
>>>>
>>>> Thanks,
>>>>
>>>> Peter
>>>>
>>>>> ------------------------------------------------------------------------
>>>>>
>>>>> 	Kevin Walls <mailto:kevin.walls at oracle.com>
>>>>> Tuesday, April 30, 2013 7:02 PM
>>>>>
>>>>>
>>>>> Hi,
>>>>>
>>>>> I'd like some review of this suggestion to fix:
>>>>> 6313816 SA windows unaligned address exception
>>>>>
>>>>> webrev:
>>>>> http://cr.openjdk.java.net/~kevinw/6313816/webrev/
>>>>>
>>>>> This bug is a long-standing annoyance, mainly shown by using 
>>>>> jstack -m
>>>>>
>>>>> Already fixed on Linux with additional sanity checks on ebp/rbp 
>>>>> values in
>>>>> e.g. LinuxX86CFrame.sender()
>>>>>
>>>>> On Windows there isn't such a convenient place to put these 
>>>>> checks, as they
>>>>> call getAddressValue() which is only part of the specific debugger 
>>>>> interfaces
>>>>> such as LinuxDebugger, WindbgDebugger, etc.. and on Windows we use
>>>>> X86CFrame and AMD64CFrame.  These are constructed with only a
>>>>> CDebugger, there is no "WinXXXFrame" class - perhaps there should be!
>>>>>
>>>>> That's what  I've tried here, by renaming e.g. X86CFrame to 
>>>>> WinX86CFrame,
>>>>> and adding the extra sanity checks as we already have in 
>>>>> LinuxX86CFrame.
>>>>>
>>>>> As files have move thed diff isn't obvious, but in common with 
>>>>> some previous changes
>>>>> the new bits are x86 and x64 versions of these:
>>>>>
>>>>> + // Check alignment of rbp
>>>>> + if ( dbg.getAddressValue(rbp) % ADDRESS_SIZE != 0) {
>>>>> + return null;
>>>>> + }
>>>>> +
>>>>>
>>>>> and
>>>>>
>>>>> - if (nextRBP == null) {
>>>>> + if (nextRBP == null || nextRBP.lessThanOrEqual(rbp)) {
>>>>>
>>>>>
>>>>> This additional symmetry between the platforms seems to make 
>>>>> sense, and
>>>>> should help any future changes.
>>>>>
>>>>> Thanks
>>>>> Kevin
>>>>>
>>>
>>

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