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LI-14190 - Looking for best memory leak procedure for linux

Posted on 2010-11-19
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Last Modified: 2012-05-10
We are using gcc --version 4.1.2.20080704 (Red Hat 4.1.2-48).  We have memory leaks that rival the water supply lines in Boston.  

We have considered making our own "new" and "delete" wrapper functions to track where this is happening, but prefer to use gdb/sdb or something else already written that would let us discover where we are not deleting objects, etc.  We are only somewhat familiar with gdb/sdb, but willing to try anything.

Anyone have suggestions/sites we can go to, to find a good procedure for finding these leaks?

Thanks!
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Question by:dgintz1217
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Anthony2000 earned 500 total points
ID: 34175367
Have you thought of using something like Valgrind?

http://valgrind.org/docs/manual/quick-start.html#quick-start.intro
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by:Anthony2000
ID: 34175740
Another technique I used in my daemon:

from in my app, I read the /proc/<my process id>/mem (I don't remember the name of the entry) it contained the amount of memory my application was consuming.

I wrote a function that would read this value and I kept a static copy of it. Later in my code, I would call call a function I called CheckMemory(). This function compared the current /proc/<my process id>mem value of my memory consumption. if it increased/decreased, I wrote to syslog. I then ran Tail on the syslog output and watched my memory change.  The CheckMemory function was really a macro that passed the __LINE__ and __FILE__ information to the log. I could then place these instrategic places in my code.

I only suggest this because it is fairly easy to do. I might even be able to find the guts of my program and share them with you. I just have to look for it.

The benefit of using this is that you don't have to learn another tool. I was able to quickly find the areas of my program that were leaking memory. In many cases it was not my New() function that was causing the problem, but, rather places where I forgot to call the close function on an open handle, etc.

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by:Duncan Roe
ID: 34186589
I hacked Tcl's memory debug package so it could be used stand_alone (without Tcl) for just this purpose.
You need to ensure that every single module which uses malloc / realloc / free has the ckalloc.h header. (If you use calloc, you'll have to write your own macro (using malloc & memset)).
At any time you like, you can call Tcl_DumpActiveMemory to get a map of all allocated memory areas with file and line number where they were allocated. You should spot the leaks fairly quickly. Good luck!
ckalloc.h
tclCkalloc.c
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by:Duncan Roe
ID: 34186613
You also have to build with -DTCL_MEM_DEBUG
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by:dgintz1217
ID: 34191033
This is c++, so its "new" and "delete".  duncan, does your solution still apply?

Thanks!
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by:Duncan Roe
ID: 34191948
Sorry no. I missed that you mentioned "new" and "delete" in your original Q. These call constructors / destructors - way out of the scope of ckalloc
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by:dgintz1217
ID: 34320288
So I will try the valgrind then at this point.
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by:dgintz1217
ID: 34764904
Will I still have access to the question and answers in my account even if the question gets closed out?
Thanks!
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by:Duncan Roe
ID: 34765436
Yes - it'll be there. You can also bookmark it by touching "save"
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by:dgintz1217
ID: 34765577
ok, we will let it close if I don't mark accept on something before 2/5.
THanks very much!
Richard
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by:evilrix
ID: 34824221
This question has been classified as abandoned and is being closed as part of the Cleanup Program. See my comment at the end of the question for more details.
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