Valgrind can't run: out of memory?

Question

I try to run a simple test with valgrind but it seems that valgrind can’t even start because of some memory limitation issue.

Command:

valgrind --leak-check=full --track-origins=yes echo 'test'

Output:

==26260==     Valgrind's memory management: out of memory:
==26260==        initialiseSector(TC)'s request for 27597024 bytes failed.
==26260==        143327232 bytes have already been allocated.
==26260==     Valgrind cannot continue.  Sorry.

Only 355/490MB of my total RAM is consumed so I would guess that is not the reason behind this since valgrind is such a small tool. Also I run the test inside a docker container if that matters.

Any idea on how to solve?

Andrew SB · Answer

One thing that it important to note here is that running a program with valgrind will require about twice as much memory as normal usage. This is because it keeps around a shadow copy of allocated memory.

The section on valgrind in this blog post about debugging tools was really helpful for me in understanding what it is up to underneath the hood:

To do this, the first thing memcheck does is to maintain a registry of all allocated memory. Every time a new chunk memory is allocated memcheck keeps track of it by remembering the returned pointer, the amount of memory allocated as well as the backtrace from which it has been allocated. Additionally, it adds some redzones around the allocated memory that cannot be allocated in order to easily detect out-of-buffer accesses.

Needless to say it will also catch every single deallocation in order to keep its registry up to date. The deallocation does not immediately remove the entry from the registry, it marks it as deallocated and remembers the deallocation backtrace. By putting deallocated memory in quarantine, it ensures that use-after-free accesses can be caught as such since that memory cannot be reused for other purpose too rapidly.

alexdo · Answer

Heya,

I’m sorry to hear about your experience. If you’re having issues with processes being killed due to memory issues you can start with examining the logs and also monitor the resource usage on your droplet.

You can check this article on how to monitor the resource usage on your droplet:

https://www.digitalocean.com/community/tutorials/how-to-use-top-netstat-du-other-tools-to-monitor-server-resources

Tools like MySQL Tunner can help you to optimize the configuration of the MySQL service by adjusting the values in the my.cnf file.

You can find more information about the MySQL tunner script in this mini tutorial here:

https://www.digitalocean.com/community/questions/how-to-tweak-mysql-mariadb-configuration-for-increased-performance-and-stability

Adding a swap file can also benefit the performance.

https://www.digitalocean.com/community/tutorials/how-to-add-swap-space-on-ubuntu-22-04

Regards