Request for review: 6310967: SA: jstack -m produce failures in output (original) (raw)

Staffan Larsen staffan.larsen at oracle.com
Thu Jun 14 02:12:05 PDT 2012

Great - where are those tests? Trying to learn my way around...

/Staffan

On 14 jun 2012, at 11:03, Poonam Bajaj wrote:

Thanks Staffan.

We do have regression tests covering jstack -m testing. regards, Poonam On 6/14/2012 2:02 PM, Staffan Larsen wrote:

Poonam, The fix looks good. It's not clear to me if there is a good regression test for this already - if not, I'd really like to see one along with the fix. Thanks, /Staffan On 14 jun 2012, at 06:10, Poonam Bajaj wrote:

Could I get one more review for this fix, please.

Thanks, Poonam On 6/13/2012 7:57 AM, David Holmes wrote:

On 13/06/2012 12:25 PM, Poonam Bajaj wrote: Hi David,

On 6/13/2012 7:35 AM, David Holmes wrote: Hi Poonam,

It seems to me that rather than passing the ThreadProxy through to f.sender the frame, which has to be a frame of some thread, should already know what that thread is and so be able to access it directly. In other words: shouldn't each CFrame maintain a reference to the thread it corresponds to? Yes, it would have made more sense to have a reference of ThreadProxy in the Frame classes. But that requires restructuring of lot more code. All the Debugger classes (e.g. agent/src/share/classes/sun/jvm/hotspot/debugger/linux/LinuxCDebugger.java) also need to be touched that have the topFrameForThread() where we create the first frame for the thread. Oh I see. I was hoping it would actually lead to fewer code changes. It seems risky to pass in a thread reference when there is only ever one valid thread reference that can be passed - but no way to verify that you actually pass the correct one. This fix was mainly for 6uxx and it didn't seem reasonable to me to restructure and touch too many classes for this simple fix. Ok. David ----- Thanks, Poonam

David On 12/06/2012 11:05 PM, Poonam Bajaj wrote: Hi, Please review this fix for bug 6310967 <http://bugs.sun.com/bugdatabase/viewbug.do?bugid=6310967>. 6310967 <http://bugs.sun.com/bugdatabase/viewbug.do?bugid=6310967>: SA: jstack -m produce failures in output http://cr.openjdk.java.net/~poonam/6310967/webrev.00/ Problem: jstack -m fails with UnalignedAddressException.The problem is that while finding the caller frame of a frame in sender() method, we don't check the validity of the frame pointer (rbp / ebp). These changes add a simple check that the frame pointer(rbp) should be a valid pointer on the stack by making sure that it is not less than the stack pointer(rsp).

Thanks, Poonam

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