- You asked: How do I find a memory leak on Linux?
- What tool is used to handle memory leak problems on Linux?
- What is a memory leak in Linux?
- How do I find a memory leak on Unix?
- What is the best tool to detect memory leaks?
- Are memory leaks permanent?
- Why are memory leaks bad?
- Do memory leaks go away?
- What process is leaking memory?
- How do I fix memory problems on Linux?
- How to Detect a Memory Leak in Ubuntu
- Detecting Memory Leaks in Ubuntu
You asked: How do I find a memory leak on Linux?
To find a memory leak, you need to look at the system’s RAM usage. This can be achieved on Windows using the resource monitor. In Windows 8.1/10: Press Windows+R to open the Run dialog; enter «resmon» and click OK.
What tool is used to handle memory leak problems on Linux?
The most popular Valgrind tool is memory checka memory bug detector that can detect problems such as memory leaks, invalid memory access, uses of undefined values, and issues related to heap memory allocation and deallocation.
What is a memory leak in Linux?
A memory leak occurs when memory is allocated and not freed after use, or when the pointer to a memory allocation is removed, making the memory no longer usable. Memory leaks degrade performance due to increased paging and, over time, cause a program to run out of memory and crash.
How do I find a memory leak on Unix?
Here are the steps that are almost guaranteed to find what is leaking memory:
- Find out the PID of the process causing the memory leak. …
- capture /proc/PID/smaps and save it to some file like BeforeMemInc. …
- wait until the memory is increased.
- recapture /proc/PID/smaps and save as afterMemInc.txt.
What is the best tool to detect memory leaks?
memory profilers are tools that can monitor memory usage and help detect memory leaks in an application. Profilers can also help analyze how resources are allocated within an application, such as how much memory and CPU time each method uses. This can help identify and narrow down any problems.
Are memory leaks permanent?
Memory leaks do not cause physical or permanent damage. Since it is a software problem, it will slow down the applications or even the entire system. However, a program taking up a lot of space in RAM doesn’t always mean that your memory is being lost somewhere.
Why are memory leaks bad?
Memory leaks are bad because your program claims resources and keeps them busy for its entire life cycleeven if you no longer need them. If you have a static leak the size of X when the program starts and it doesn’t grow over time, that’s unfortunate, but probably not the end of the world.
Do memory leaks go away?
It was normal to see messages like “Out of memory! try downloading some of your TSRs” when working on these operating systems. So technically the program is terminated, but because it still resides in memory, any memory leaks will not be released unless you download the program.
What process is leaking memory?
In computing, a memory leak is a type of resource leak that occurs when a computer program incorrectly manages memory allocations so that memory no longer needed is not freed. A memory leak can also occur when an object is stored in memory but cannot be accessed by running code.
How do I fix memory problems on Linux?
- The process stopped unexpectedly. …
- Current use of resources. …
- Check if your process is at risk. …
- Disable on commitment. …
- Add more memory to your server.
How to Detect a Memory Leak in Ubuntu
There are several reasons a memory leak might occur on Ubuntu, but fortunately, it’s obvious when they do occur. Buggy code is often the biggest reason, since programmers might not have had the opportunity to check to ensure that memory that’s no longer needed gets released. If you’ve been installing unstable packages or compiling code from source, then you might be dealing with memory leaks for this reason. You’ll probably start noticing them because software application packages start to complain about being out of memory when you have more than enough physical RAM installed.
If you’re concerned about a memory leak, try typing free repeatedly into a terminal. If you suddenly start to see RAM use quickly growing, then you’ve already detected a memory leak. Should you receive an error that reads something like bash: Not enough Memory while doing this and you have nothing but a terminal or even just a virtual console open, then you’re almost unquestionably dealing with one. Some memory leaks can be a bit subtler, but Ubuntu and it’s various spin-offs feature tools and packages that can help you detect these.
Detecting Memory Leaks in Ubuntu
Since the tools used for detecting memory leaks are primarily based around the CLI prompt, it doesn’t matter which version of Ubuntu you run them on. These should work fine inside of a Unity terminal in regular Ubuntu, from a virtual console in Ubuntu Server, from an lxterm in Lubuntu, a Konsole in Kubuntu or even inside of Xfce in Xubuntu. Try performing a simple task like sudo -s and type your password to begin.
This should get you a root shell if performed correctly, but may cause a memory error if you’re working with a leak that’s already gone too far. If you’re indeed able to access a root shell, then try typing echo 3 > /proc/sys/m/drop_caches, push the enter key and then type exit. Try running free or free -m again to see if that’s helped to release memory.
Some programmers argue that there’s no point in forcing the Kernel to drop out its caches, since they should be flushed and thus reclaimed as soon as additional physical memory is needed. However, while force flushing these caches will hurt system performance keep in mind that this is merely a test. Once you’ve rebooted the system, the Linux Kernel should once again assemble the memory caches the way that they were in the first place.
A few people have suggested adding the line sync; sudo echo 3 > /proc/sys/vm/drop_caches to a script that cron runs consistently, but this defeats the purpose of memory caching in the first place. Free memory itself is merely unused RAM, and that means that data has to be loaded from much slower electromechanical or NAND storage devices. No matter how fast these devices are, they’re not as fast as RAM is, which means that while you should fix memory leaks, you shouldn’t actually tamper with the cache system once you have it set to the optimal setting.
If you’ve decided you indeed have a consistent memory leak that happens periodically while using your machine and it can’t be narrowed down specifically, but you still have CLI access, then try running the top command. This should give you a list of running processes.
Should Ubuntu give you an unusual error about top then try issuing busybox top instead in order to access an even simpler version of this program. Once you have a list, look at the %MEM or similar column to see which applications are assigned the most memory. While you could note the PID and issue a kill command to the exact number of the PID, this will merely force the application to close. The memory they use might still not be released after you do this, though it’s of course worth a shot.
If you find an application that’s using a large amount of memory, push q to quit and then try kill #### with the PID number from the previous screen. System processes should not be killed this way, nor should anything that you have unsaved work in. Think of this similarly to killing something with the Ctrl+Alt+Del task list, which you can also use for this same process.
When you’ve found a program that this is consistently happening to, then you can configure it to prevent the behavior in the future. Each individual program, of course, will need a different recourse, which is beyond the task of merely detecting memory leaks.
Should you not be merely troubleshooting applications, but also actually working with code then there are a few other recourses you have. Ubuntu and its derivatives offer you the membarrier, memusage and memusagestat C routines for programming.
Simply use man membarrier, man memusage or man memusagestat to view the Linux Programmer’s Manual pages on these important routines. If there are upgrades in future versions of the libraries as new versions of Ubuntu come out, then the changes will always be outlined here.
If you need graphical content, then memusagestat even offers the option to save a graphical representation of memory use to a PNG file. This makes it an attractive feature for authors of utilities as well, since it can be used to make applications that regularly check for memory leaks.
You may also wish to install memprof, which is a tool for profiling memory usage in order to aid you in finding memory leaks. It generates a profile regarding how much memory each function in a program you’re writing allocates. It can also scan existing memory to find blocks, which have been allocated, but no longer feature genuine references. It does this by pre-loading a library in order to override the standard C library’s memory allocation features.
If you plan to use this, then make sure to remove the include memprof line from the beginning of your code before releasing it. This is used to make sure you have no leaks, but it shouldn’t become a dependency if you package your code and release it in a repository.