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The main content of this article is to explain "what is the role of Linux core dump", interested friends may wish to take a look. The method introduced in this paper is simple, fast and practical. Let's let the editor take you to learn "what is the function of Linux core dump"?

When the process crashes, Linux will save the memory state of the pre-crash process in the core file, just like saving the photos of the crime scene, which can help developers find the cause of the accident and fix the program. This article uses a simple example to explain how to locate the cause of a process crash according to the core file.

First of all, write C++ code, define a null pointer, write to the memory area pointed to by the null pointer, and coretest01.cpp # include int main () {int * p = NULL; * p = 10;}

Compile the executable file coretest01, run the print out core dumped, and the core file should appear.

However, there is no core file generated in the directory, which is prohibited by the system setting. Use ulimit-a to check the system's settings for core files. The core file size setting is 0, which means that core files are not allowed to be generated. Change the configuration to unlimited, with no limit on the size. Execute coretest01, which produces the core file, followed by the process number of the crash process. To view the core file information, use the gdb command, execute bt and where under [root@webserver code] # gdb coretest01 core.1953gdb, you can see the location of the code that crashed the program, but now you can only see the main function, not other specific information. This is because there is no debugging information added when compiling the code, the parameter of adding debugging information is-g you can see that after adding debugging information, the core file can accurately tell the error code file and in which line, line 5 is the place where the code null pointer points to the area write operation. The actual production system often has a lot of executable files in the same directory, aserver bserver. Wait. When a core file appears, we first have to determine which executable generated the core file before we can troubleshoot the problem. The command file core can help us determine which executable generated the core. Then write a code file coretest02.cpp # include int main () {int * p2 = NULL; * p2 = 10 } compile to generate an executable file coretest02, run two executable files, there will be two core files file core.* can correctly indicate which executable file the core file comes from (no matter what the executable file is, even if it is java,Python, it is the same operation), and then the gdb executable file core.*, can check the cause of the error.

At this point, I believe you have a deeper understanding of "what is the role of Linux core dump". You might as well do it in practice. Here is the website, more related content can enter the relevant channels to inquire, follow us, continue to learn!

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