Shulou(Shulou.com)06/01 Report--

This article mainly explains "what are the common causes of Linux crash". 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 are the common causes of Linux crash.

In addition to troubleshooting hardware problems / firmware version / BIOS, etc., Linux crashes may usually encounter the following situations

1, if your Linux crashes, there are messy characters on the console. Congratulations, this situation is called oops. It is usually caused by Linux kernel's belief that something unusual has happened to him.

You can use oops messages to find out what went wrong.

2, if your machine is dead, then the problem is troublesome. At times like this, it is usually the Kernel that has a deadlock. Kernel won't know it's deadlocked, so it won't show any drumming on the screen.

With any luck, Kernel may be able to respond to interrupts at this point. In any case, you can't go any further.

3, strictly speaking, this third case is not a crash, and the phenomenon is as follows: after entering the command enter, the command cannot return any results, but the console may have a corresponding response to the enter. But the command does not end, and there is no output.

But you can switch to the next console, and you can continue to enter the command, but there is still no output after entering the command. There are many possibilities for this situation. Usually, the system call of the application does not return for a long time or can not meet the requirements of the application.

In the above three cases, the role of system log is not significant. Usually the log is not recorded. So you can only use Kernel's Debug tool.

But Linus is ruthless. People say that Kernel doesn't need Debug tools. So there is no debug tool for the code in kernel.org. At present, however, most distributions of kernel come with debug tools, and the tools are different.

Usually for kernel debug, it is necessary to collect vmcore in case of failure. Is to memory dump out when the fault occurs. (remember that a number and c disk dump.sys file will appear when the Windows blue screen beats at 1% Murray 100%. Do you know what to do this time?) and then analyze it. Maybe you will worry about Linux crashing, how to dump memory ah, don't worry about this, Kernel still left several ways. One of them is NMI.

So how to dump memory in the end? Take REDHAT as an example, netdump is used as the acquisition tool in RHEL3,RHEL4, and kdump is used as the acquisition tool in RHEL5.

After the collection, the vmcore can be analyzed, and the steps will not be detailed. You can refer to the following article: http://people.redhat.com/anderson/crash_whitepaper/

But for administrators, any debug tool requires code development experience to be used smoothly.

Finally, recently, I saw someone in the altar who saw the crash and doubted the application. This is a good spirit of self-criticism and should be vigorously carried forward.

So, will the script, the application, cause a crash? Sure, but the problem still lies with Kernel. For example, if an application writes files, the system may hang on the file system code in kernel.

At this point, I believe you have a deeper understanding of "what are the common causes of Linux crash?" 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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