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Operating Systems Linux Red Hat Free() corrupted unsorted chunks Post 302843630 by Don Cragun on Wednesday 14th of August 2013 08:28:48 AM
Old 08-14-2013
There is nothing magical about a bad pointer problem going undetected for years. Depending on what the problem is, the same source code built using a different compiler, running on different hardware, or even running it at a different time of day may mask a problem until the right sequence of events happens in your program to expose the problem. 99.44% of the time (at least in my experience looking at bug reports against Solaris systems), the bug is in your code. The rest of the time, it may be a bug in the kernel, in a system library, or a hardware problem.

Without carefully analyzing your code, there is no way to guess at what the problem might be. You basically need to look at every line of code that allocates space, every line of code that uses a pointer (or an array subscript), and every line of code that frees space to verify that the pointer/array subscript is in bounds for the space allocated to that space/array) and that allocated space is not referenced after it is freed.

If you show us your code, we might spot the problem in seconds, or we might never figure it out. If you don't show us your code, there isn't anything we can do to help you other than suggest that you set breakpoints in your code, dump variables that seem to be corrupted, and add debugging statements until you identify the problem and fix it. But, be aware that adding a line of debugging code can easily change the way your program runs just enough to hide a problem. I.e., debugging bad pointers can be really hard.

You have not said anything yet that sounds like there was a bug on your old Solaris system nor that there is a bug on your new Linux system (although subtle differences in the ways functions are defined to behave on the two systems may well be your problem).
 

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INTRO(9)						   BSD Kernel Developer's Manual						  INTRO(9)

NAME
intro -- introduction to system kernel interfaces DESCRIPTION
This section contains information about the interfaces and subroutines in the kernel. PROTOTYPES ANSI-C AND ALL THAT Yes please. We would like all code to be fully prototyped. If your code compiles cleanly with cc -Wall we would feel happy about it. It is important to understand that this is not a question of just shutting up cc, it is a question about avoiding the things it complains about. To put it bluntly, do not hide the problem by casting and other obfuscating practices, solve the problem. INDENTATION AND STYLE
Believe it or not, there actually exists a guide for indentation and style. It is not generally applied though. We would appreciate if people would pay attention to it, and at least not violate it blatantly. We do not mind it too badly if you have your own style, but please make sure we can read it too. Please take time to read style(9) for more information. NAMING THINGS
Some general rules exist: 1. If a function is meant as a debugging aid in DDB, it should be enclosed in #ifdef DDB #endif /* DDB */ And the name of the procedure should start with the prefix DDB_ to clearly identify the procedure as a debugger routine. SCOPE OF SYMBOLS
It is important to carefully consider the scope of symbols in the kernel. The default is to make everything static, unless some reason requires the opposite. There are several reasons for this policy, the main one is that the kernel is one monolithic name-space, and pollution is not a good idea here either. For device drivers and other modules that do not add new internal interfaces to the kernel, the entire source should be in one file if possi- ble. That way all symbols can be made static. If for some reason a module is split over multiple source files, then try to split the module along some major fault-line and consider using the number of global symbols as your guide. The fewer the better. SEE ALSO
style(9) HISTORY
The intro section manual page appeared in FreeBSD 2.2. BSD
December 13, 1995 BSD
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