[gecode-users] Heap memory free error

[Christian Schulte]

Hi,

I went through the changelog to get an idea what might have happened and I
have a theory: 3.5.0 fixes a memory-management related bug in parallel
search (which you seem to use, right?). And you seem to use Windows, which
compiler, ...

What is a likely explanation is that this fixes triggers a potential bug in
your code. Let me guess some more: you have implemented your own brancher.
Does this brancher use some data structures (such as sharedarray etc?). Does
the copy() function of the brancher take the Boolean share flag into account
during cloning? If it is false the brancher must create an independent copy
even for a shared data structure as it is going to be used in a different
thread. Check also MPG about this.

Could that be related?

Otherwise, there is no change in memory management in Gecode. Another
possible explanation might be that some allocation/deallocation is no
happening in different DLLs which is not allowed on Windows (that's a well
known bug in Windows). Could you test on Linux whether this happens on Linux
as well? I could see that if you send me the brancher code.

Cheers
Christian 

--
Christian Schulte, www.ict.kth.se/~cschulte/


-----Original Message-----
From: users-bounces at gecode.org [mailto:users-bounces at gecode.org] On Behalf
Of Maity, Ashis K
Sent: Tuesday, June 14, 2011 11:59 PM
To: cschulte at kth.se; users at gecode.org
Subject: [gecode-users] Heap memory free error

Hello,

Recently I upgraded my Gecode from 3.4.2 to 3.5.0. I have been running my
old problems to do sanity check. While many of the old problems do run fine
in newer version, I am getting this strange error on some problems and can't
figure out the reason. These problems still run fine when I use a server
that is running old version of the Gecode. I tried cleaning, rebuilding,
restarting, reloading etc. Any help is appreciated.
--------------------------
HEAP[AutomatedScheduler++.exe]: Invalid Address specified to RtlFreeHeap(
00B90000, 015059B0 )
Windows has triggered a breakpoint in AutomatedScheduler++.exe.

This may be due to a corruption of the heap, which indicates a bug in
AutomatedScheduler++.exe or any of the DLLs it has loaded.

This may also be due to the user pressing F12 while AutomatedScheduler++.exe
has focus.

The output window may have more diagnostic information.



--- Here is the stack trace ---
	ntdll.dll!7c90120e() 	
 	[Frames below may be incorrect and/or missing, no symbols loaded for
ntdll.dll]	
 	ntdll.dll!7c96ee31() 	
 	ntdll.dll!7c96f26e() 	
 	ntdll.dll!7c970456() 	
 	ntdll.dll!7c94bafc() 	
 	ntdll.dll!7c91a1ba() 	
 	ntdll.dll!7c91a351() 	
 	msvcr90.dll!78583c1b() 	
>	AutomatedScheduler++.exe!Gecode::Heap::rfree(void * p=0x015795e0)
Line 332 + 0xc bytes	C++
 
AutomatedScheduler++.exe!Gecode::Heap::free<Gecode::IntVar>(Gecode::IntVar *
b=0x015795e0, unsigned long n=18)  Line 385	C++
 
AutomatedScheduler++.exe!Gecode::Heap::free<Gecode::IntVar>(Gecode::IntVar *
b=0x015795e0, int n=18)  Line 402	C++
 
AutomatedScheduler++.exe!Gecode::ArgArrayBase<Gecode::IntVar>::~ArgArrayBase
<Gecode::IntVar>()  Line 1579	C++
 
AutomatedScheduler++.exe!Gecode::VarArgArray<Gecode::IntVar>::~VarArgArray<G
ecode::IntVar>()  + 0x58 bytes	C++
 	AutomatedScheduler++.exe!Gecode::IntVarArgs::~IntVarArgs()  + 0x58
bytes	C++
 	AutomatedScheduler++.exe!Scheduler::postResourcePick()  Line 213 +
0x5a bytes	C++
 	AutomatedScheduler++.exe!Scheduler::afterResourcePick(Gecode::Space
& home={...})  Line 108	C++
 	GecodeKernel-3-5-0-r-x86.dll!Gecode::FunctionBranch::commit()  + 0xf
bytes	C++
 	GecodeKernel-3-5-0-r-x86.dll!Gecode::Space::_commit()  + 0xf1 bytes
C++
 
GecodeSearch-3-5-0-r-x86.dll!Gecode::Search::WorkerToEngine<Gecode::Search::
Sequential::BAB>::next()  + 0x149 bytes	C++
 	AutomatedScheduler++.exe!Gecode::BAB<Scheduler>::next()  Line 57 +
0x20 bytes	C++
 	AutomatedScheduler++.exe!threadFunction(void * a=0x00b965a8)  Line
231 + 0xb bytes	C++
 	AutomatedScheduler++.exe!ThreadWrapper<void *>::Execute()  Line 321
+ 0x18 bytes	C++
 	AutomatedScheduler++.exe!ThreadWrapper<void
*>::ThreadRoutingFunction(void * pParam=0x00b96558)  Line 274	C++
 	msvcr90.dll!78543433() 	
 	msvcr90.dll!785434c7() 	
 	kernel32.dll!7c80b729() 

----------------
Thanks,

Ashis	

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