Debug Heap Corruption Error

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Debug Heap Corruption Visual Studio

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Detect Heap Corruption

errors? up vote 127 down vote favorite 83 I am debugging a (native) multi-threaded C++ application under VisualStudio2008. On seemingly random occasions, I get a "Windows has triggered a break point..." error with a note that this might be due to a corruption in the heap. These errors won't always crash the application right away, although it is likely to crash short after. The big c++ detect heap corruption problem with these errors is that they pop up only after the corruption has actually taken place, which makes them very hard to track and debug, especially on a multi-threaded application. What sort of things can cause these errors? How do I debug them? Tips, tools, methods, enlightments... are welcome. c++ windows debugging heap share|improve this question edited Jan 24 '13 at 20:21 Peter Mortensen 10.2k1369107 asked Jun 18 '09 at 0:01 Beef add a comment| 13 Answers 13 active oldest votes up vote 99 down vote accepted Application Verifier combined with Debugging Tools for Windows is an amazing setup. You can get both as a part of the Windows Driver Kit or the lighter Windows SDK. (Found out about Application Verifier when researching an earlier question about a heap corruption issue.) I've used BoundsChecker and Insure++ (mentioned in other answers) in the past too, although I was surprised how much functionality was in Application Verifier. Electric Fence (aka "efence"), dmalloc, valgrind, and so forth are all worth mentioning, but most of these are much easier to get running under *nix than Windows. Valgrind is ridiculously flexible: I've debugged large server software with many

24, 20083 0 0 0 When dynamic allocation/deallocation of memory is not handled properly by user code, this might lead to memory blocks in the heap being corrupted. There are many causes of heap corruption. Some of the common causes are: Buffer overrun (Writing

Heap Corruption Detected After Normal Block

beyond the allocated memory), Double free (Freeing a pointer twice) and Old pointer reuse(Reusing a

Heap Corruption Detected By Dlmalloc

pointer after being freed). The difficulty with troubleshooting heap corruption is because when a thread for instance corrupts the heap, the heap corruption detected free list canary is damaged process does not terminate or throws an error! As long as the corrupted heap is not used, the process will not crash, but once a thread tries to use that corrupted block of memory in the http://stackoverflow.com/questions/1010106/how-to-debug-heap-corruption-errors heap, the process crashes! If a crash rule is active and the process crashes because of heap corruption, what we would see as a “culprit” thread that caused the crash is actually nothing more than a victim thread! So to get to the root of the problem and find out the cause of the corruption, that is the thread that corrupted the heap, Pagegeap should be enabled. Pageheap could be enabled directly in https://blogs.msdn.microsoft.com/lagdas/2008/06/24/debugging-heap-corruption-with-application-verifier-and-debugdiag/ debugdiag via a crash rule and would provide the desired results, but if you would want to get more granular information about the corruption to simplify the code fix, Application verifier could be used in conjunction with debugdiag to get such information. To turn on pageheap for the worker process w3wp.exe and attach the debugdiag debugger host to it, here is how to do that: First, download and install both tools: - Download and Install Debugdiag 1.2 - Download and Install Application Verifier v3.4 - Start Application Verifier (Start -> Programs -> Application Verifier -> Application Verifier). - Click File -> Add Application and browse to C:\Windows\System32\Inetsrv\w3wp.exe - In the Tests Panel, expand Basics checkbox and uncheck all except Heaps - In the Tests Panel again, select Heaps checkbox and click Edit -> Verifier Stop Options This basically shows the stop codes that application verifier generates. The defaults actions are for all stop codes. The most important action here is the "Breakpoint" in the Error Reporting section which means that Application Verifier will call into the breakpoint exception when it detects that the heap is being corrupted. - Start Debugdiag (Start -> Programs -> Debug Diagnostic Tool 1.2 -> Debugdiag 1.2 - Add a crash rule against a specific process. - Type in

detection and covers the following topics: "Typical Heap Corruption Problems" "Finding Heap Corruption Errors" "Heap Corruption Detection Tutorial" Typical Heap Corruption Problems Due to the dynamic nature of allocating and deallocating memory, the heap is http://csweb.cs.wfu.edu/~torgerse/Kokua/More_SGI/007-2579-009/sgi_html/ch09.html vulnerable to the following typical corruption problems: boundary overrun: a program writes beyond the malloc region. boundary underrun: a program writes in front of the malloc region. access to uninitialized memory: a program attempts to read memory that has not yet been initialized. access to freed memory: a program attempts to read or write to memory that has been freed. double frees: a program frees some structure heap corruption that it had already freed. In such a case, a subsequent reference can pick up a meaningless pointer, causing a segmentation violation. erroneous frees: a program calls free() on addresses that were not returned by malloc, such as static, global, or automatic variables, or other invalid expressions. See the malloc(3f) man page for more information. Finding Heap Corruption Errors To find heap corruption problems, you must relink debug heap corruption your executable with the -lmalloc_ss library instead of the standard -lmalloc library. By default, the -lmalloc_ss library catches the following errors: malloc call failing (returning NULL) realloc call failing (returning NULL) realloc call with an address outside the range of heap addresses returned by malloc or memalign memalign call with an improper alignment free call with an address that is improperly aligned free call with an address outside the range of heap addresses returned by malloc or memalign If you also set the MALLOC_FASTCHK environment variable, you can catch these errors: free or realloc calls where the words prior to the user block have been corrupted free or realloc calls where the words following the user block have been corrupted free or realloc calls where the address is that of a block that has already been freed. This error may not always be detected if the area around the block is reallocated after it was first freed. Compiling with the Malloc Library You can compile your executable from scratch as follows: % cc -g -o targetprogram targetprogram.c -lmalloc_ssYou can also relink it by using: % ld -o targetprogram targetprogram.o -lmalloc_ss ...An alternative to rebuilding your executable is to use th