Identifying Memory Leaks in Linux for C++ Programs

Identifying Memory Leaks in Linux for C++ Programs

Most C++ programmers agree that it can be harrowing trying to identify the memory leaks in a given program.

If you’re working on the GNU/Linux platform, there’s an interesting tool you can use to minimize the hassle of this task: mtrace.

Here’s some background on mtrace:

  1. You call the mtrace() function to log all memory leaks. The memory allocations and deallocations are logged to a text file pointed to by the environment variable?MALLOC_TRACE.
  2. A Perl utility called mtrace parses the text file logged by your program and identifies the memory leaks.

The following code allocates memory, but does not essentially free it:

#include int main() { 	int *a;	a = malloc(sizeof(int)); //Allocate memory		*a = 7;	//Notice that we are not freeing memory before we end the program. 		return EXIT_SUCCESS;}

Now, see how to use mtrace to identify the memory leak:

  • Step 1: Setup MALLOC_TRACE environment variable to point to a file where mtrace needs to log the memory allocations:
          setenv MALLOC_TRACE  /home/karthik/temp/trace.txt 
  • Step 2: Insert mtrace hooks into the program:
    #include #include  /* Header file to include mtrace related functions */int main() { 	int *a;	mtrace(); /* This starts memory tracing. This has to be done before we do a 'malloc' or we allocate memory.  */		a = malloc(sizeof(int));  /* Allocate memory */		*a = 7;	/* Notice that we are not freeing memory before we end the program.  */		return EXIT_SUCCESS;}
  • Step 3: Compile the modified program with the debugging options turned on:
        $ gcc -g -Wall -ansi -pedantic leak.c
  • Step 4: Run the program.
  • Step 5: Use the mtrace utility to retrieve the information. Here’s what the syntax looks like:
    mtrace   [[email protected] work]$ mtrace a.out ~/temp/trace.txtMemory not freed:-----------------   Address     Size     Caller0x08049910      0x4  at /home/karthik/tips/leak.c:9

This precisely tells you that there is a potential memory leak at line 9:

  a = malloc(sizeof(int));  /* Allocate memory */ 

mtrace is a GNU utility.

The code in this tip was tested on a Linux platform with the gcc 3.2.3.

Share the Post:
XDR solutions

The Benefits of Using XDR Solutions

Cybercriminals constantly adapt their strategies, developing newer, more powerful, and intelligent ways to attack your network. Since security professionals must innovate as well, more conventional endpoint detection solutions have evolved

AI is revolutionizing fraud detection

How AI is Revolutionizing Fraud Detection

Artificial intelligence – commonly known as AI – means a form of technology with multiple uses. As a result, it has become extremely valuable to a number of businesses across

AI innovation

Companies Leading AI Innovation in 2023

Artificial intelligence (AI) has been transforming industries and revolutionizing business operations. AI’s potential to enhance efficiency and productivity has become crucial to many businesses. As we move into 2023, several

data fivetran pricing

Fivetran Pricing Explained

One of the biggest trends of the 21st century is the massive surge in analytics. Analytics is the process of utilizing data to drive future decision-making. With so much of

kubernetes logging

Kubernetes Logging: What You Need to Know

Kubernetes from Google is one of the most popular open-source and free container management solutions made to make managing and deploying applications easier. It has a solid architecture that makes

ransomware cyber attack

Why Is Ransomware Such a Major Threat?

One of the most significant cyber threats faced by modern organizations is a ransomware attack. Ransomware attacks have grown in both sophistication and frequency over the past few years, forcing

data dictionary

Tools You Need to Make a Data Dictionary

Data dictionaries are crucial for organizations of all sizes that deal with large amounts of data. they are centralized repositories of all the data in organizations, including metadata such as