Rust lang memory leak. If you want to obtain a raw pointer to the memory, see Box::into_raw. Rust guarantees memory safety, not “no leaks ever. I am monitoring my resources and when I see it goes over 6. 04 and I have a program a. and it is funy that c and cpp don't have memory leak with same code and even they are 4/5 sec faster than rust (with optimize and without optimize. org To enable a sanitizer compile with -Zsanitizer=address, -Zsanitizer=cfi, -Zsanitizer=dataflow, -Zsanitizer=hwaddress, -Zsanitizer=leak, -Zsanitizer=memory, -Zsanitizer=memtag, -Zsanitizer=realtime, -Zsanitizer=shadow-call-stack or -Zsanitizer=thread. OP mentioned an FFI, potentially to a memory-unsafe language like C. Do I understand it right that it is possible to leak memory by shadowing the variable in the same scope? I mean in principle - I understand that the issue is easily solvable by clippy if need be. We can see that Rust allows memory leaks by using Rc<T> and RefCell<T>: it’s possible to create references where items refer to each other in a cycle. The only way to improve the memory usage is by changing the requirement. In this article we will explore some cases where leaking memory is useful. And that distinction matters more than most developers realize — especially those coming from C++ or Java backgrounds. Here’s a bold truth: Rust is memory safe, but not memory leak-proof. ” It’s entirely possible — sometimes even desirable — to leak memory on purpose. Here it is. On startup, GNOME System Monitor shows: virtual memory: 1. I've tried googling, but can't find where to even begin to look for how to debug what is causing this memory leak. Generally, a structure circularly referencing itself, either directly or indirectly, should not hold a strong reference to itself to prevent a memory leak. When running my program, I'm seeing high memory usage. 5 MB Question #1: My binary's size is 23 M. However, that doesn’t say anything about other types of memory leaks. I just see in task manager how RAM grows when app is running. /rustcode. For example, if you have two Rc s pointing at each other, they'll never be deallocated (which is why the Weak type exists). extern crate piston_window; extern crate image as im; use piston_window::*; use piston Leaking data The main concern around passing references to spawned threads is use-after-free bugs: accessing data using a pointer to a memory region that's already been freed/de-allocated. rs use ::core::{convert::TryInto, slice}; use ::libc::size_t; use python memory-leaks memory memory-profiler memory-leak memory-leak-detection memory-leak-finder memory-profiling memory- Updated on Jan 19 Rust Preventing memory leaks entirely is not one of Rust’s guarantees in the same way that disallowing data races at compile time is, meaning memory leaks are memory safe in Rust. If this chapter has piqued your interest and you want to implement your own smart pointers, check out “The Rustonomicon” for more useful information. As an example, from a previous question on this board (Passing vector of vectors buffer to C), I have the following implementation: lib. 8 GB resident memory: 11. Despite their potential for destruction, Rust considers memory leaks "memory safe" and thus doesn't aim to prevent them. We have blogged before about pivoting some of our core business systems to Rust, how the language has changed… I'm new to Rust. Could somebody help me to detect where is memory leak ? What are the common practices and approaches ? Rust doesnt protect from memory leak, thats why a leak its still a possibility Valgrind used to require you to change the allocator to work correctly, I dont know if this have changed, but I used it recently with the default allocator and it did deetect the leak correctly , so some reasarch might be needed if you're going to use it 1 Like Software analysis tools can detect many instances of memory management issues and operating environment options can also provide some protection, but inherent protections offered by memory safe software languages can prevent or mitigate most memory management issues. This can be done, for example, using the . The similarity of the phrases "memory leak" and "memory safety" regularly tricks people who have read "Rust is memory safe" into thinking Rust is (just) preventing memory leaks, leading to legitimate doubts about what Rust offers instead of, say, modern C++ in the space of low-level systems languages. rust-lang / rust Public Notifications You must be signed in to change notification settings Fork 13. as we know rust , rust is safe and fast programming language but why in this code it is slower and even has memory leak? Explore Rust's borrow checker and learn how it enhances code safety, prevents errors, and the principles behind it. However, it does not guarantee that pointers to this memory will remain valid. 8k Star 107k Whether that's a real memory leak or not can be kind of subjective. If you’re working with other languages that are also instrumented with sanitizers, you I have a memory leak in my app. I reduced app to the very small example, and I can't understand where memory goes. However, we observed that user intervention drives it into semi-automated memory management and makes it error-prone to cause leaks The Rust programming language gives us the power to manage memory in a safe and efficient way, ensuring we don't have to deal with those dreaded segfaults and memory leaks. Let’s explore both with working code examples you can run yourself. Rust is an effective system programming language that guarantees memory safety via compile-time verifications. That aspect of Rust doesn’t seem to be talked about enough when people compare Rust vs. The data structure never touches the loop variable. Hi guys, I am giving rust a try as a possible replacement for C++. I am reading through "The Book" (which is BTW excellent) and got surprised by variable binding shadowing. Oct 15, 2025 · Rust provides two main pathways to leak memory, each revealing different aspects of the language’s design philosophy. Using this function, you get access to the weak pointer during the initialization of T, before the Arc<T, A> is created, such that you can clone and store it inside the T. In case this helps, this is my app: GitHub - idewave/idewave-cli at dev. Jan 5, 2026 · This article focuses on how memory-leak prevention is implemented in the Rust language, specifically through a set of compile-time rules known as ownership and borrowing rules. Has anyone else in the Rust community tried to fix unloading of dynamic libraries? for example, memory leaks due to the thread-locals (on linux), leaked memory in static s (they dont even have destructors in runtime) So far I only found this great article: So you want to live-reload Rust (which partially helps with thread-locals on linux) also found these repos GitHub - emoon/dynamic_reload You are putting a million items into a per-worker HashMap. ptr where you should have used the newly generated ptr. c. Should memory leaks due to other problems (such as a closure that violates a contract being passed by the user) be considered to violate memory safety? At OneSignal, we love Rust. note: Linux & Windows While working on a multi-threaded Rust process that passes work from one thread to another over a channel, I've noticed a memory leak that (the initial allocation at least) appears to be occurring as a result of building a Vec of PathBufs. Open for discussions! You are putting a million items into a per-worker HashMap. It employs a novel ownership-based resource management model to facilitate automated deallocation. 1 MB shared memory: 8. NSA recommends using a memory safe language when possible. Rust Programming: Safe & High-Performance System Development What if you could build system-level software that is both blazingly fast and memory safe without a garbage collector? That’s exactly A place for all things related to the Rust programming language—an open-source systems language that emphasizes performance, reliability, and productivity. When I create a Node, I'm encountering a memory leak issue. as we know rust , rust is safe and fast programming language but why in this code it is slower and even has memory leak? Hey guys, I'm working on a B+ tree implementation, and I've hit a snag. Zig, and definitely should be considered if you’re going to be doing memory-unsafe things for performance. If you encounter any unusual memory usage issues, you might find this article helpful for quick diagnostics and identification of potential memory leaks. org Rust Playground A browser interface to the Rust compiler to experiment with the language I couldn't replicate the leak on MIRI, but I did find some UB , you accidentally used self. (to run Miri in Playground, go to Tools in the top right corner then run Miri) The problem is a memory leak that apparently happens at ABI for my FFI where I am constructing an c++ object (which is basically an in memory db ) and try to repeatedly get a pattern from it. Any insights on what might be causing this memory leak or I'm writing something like lending iterator: use std::marker::PhantomData; use std::mem::forget; use std::ptr::NonNull; use itertools::{Itertools, TupleWindows Here in this blog, I shared my experience and detailed techniques for troubleshooting memory leak issues based on Jemalloc. However where we must be careful with destructor leaks are proxy types. Nov 20, 2024 · Learn how to manage memory leaks in Rust, avoid unsafe behavior, and use tools like Weak references to ensure efficient programs. The important bit is understanding how leaks happen in Apr 1, 2025 · Although is way more difficult to leak memory in Rust than in other languages, it can happen, sometimes by accident, and sometimes, by design. I thought the memory usage would be at least the size of the binary. I'm still learning unsafe and miri, so I'm unsure what's causing this problem. If it does, can you provide a simple example? Furthermore, how rust handels with memory leaks? I read that Rust handles with 'dangling references' by using the lifetime feature, is there something similar in Rust? mayabe a Garbage collector? Memory leakage in Rust is completely safeuntil you run out and it results in your program being killed by the kernel. Learn how to manage memory leaks in Rust, avoid unsafe behavior, and use tools like Weak references to ensure efficient programs. I have been working with opentelemetry-rust crate, during the usage I found that one particular function in this crate has memory leak (using this function is resulting high usage of RSS memory), Memory Consumption Issue… Preventing memory leaks entirely is not one of Rust’s guarantees in the same way that disallowing data races at compile time is, meaning memory leaks are memory safe in Rust. The main goal of this project is to build a basis for hot reload (or live reload) for (almost) normal Rust programs, ability to spawn threads, use static variables, etc. And this is actually not the hardest thing to do. You can also leak memory if you create a cycle of shared references: A cycle between Rc pointers will never be deallocated. If you want to leak memory, see Box::leak. In practice, programmers usually write Rust code in conjunction with other languages such as C/C++ Yes, you correctly read, “produce a Memory Leak in Rust”. In the following example a string slice &'a str implements the trait TraitExample, and the function example_func takes anything that implements the trait. We explored reference cycles that can cause memory leaks and how to prevent them using Weak<T>. Learn how we solved this issue to eliminate memory leaks. Oddly, I don't encounter any issues when creating a Leaf, but the problem arises when I attempt to wrap Leaf with Node::LEAF. Nearly all garbage collected languages have hidden allocations strewn about, since the garbage collector hides the evidence on the cleanup side. also you can see that just do valgrind . https://doc. If you are using the memory throughout the program's runtime and there's no particular point before the end of the program when it would make sense to delete it, is that really a leak? 5 play. For this reason, Weak is used to break cycles. Hello, I&#39;m confusing to dealing with memory leak in rust. update it hogs all memory (gigabytes of it!) in seconds. Why is it lower? After running a task (it's a server which uses smol as a multithreaded executor), System Monitor shows According to the reference, “Leaks due to reference count cycles, even in the global heap” is not unsafe. Now I've found, monitoring my resources that just typing "Free" in the console will bring the game, at least on my system, to about 5. Is there a way of causing a memory leak in Rust? I know that even in garbage collected languages, like JavaScript, there are edge cases where memory will be leaked. For most types this doesn't matter: if you leak the destructor then the type is by definition inaccessible, so it doesn't matter, right? For instance, if you leak a Box<u8> then you waste some memory but that's hardly going to violate memory-safety. As someone who loves Rust, I’m definitely going to explore using Zig more for projects. The problem is a memory leak that apparently happens at ABI for my FFI where I am constructing an c++ object (which is basically an in memory db ) and try to repeatedly get a pattern from it. The main Rust standard library APIs panic on out of memory conditions, and the alternate APIs that accept allocator parameters are an afterthought (see rust-lang/rust#29802). Any resources the value manages, such as heap memory or a file handle, will linger forever in an unreachable state. Are there any such cases in Rust? In certain cases Rust doesn’t have enough information to make this conversion, known as Deref coercion. If you uncomment texture. 5 gb I type "free", and for about 20-25 Common causes of memory leaks include lingering references to unused objects in memory, mishandled pointer operations, or bypassed deallocation routines. Here's a stripped down example: The first thread collects the Vec of PathBufs from the values of a HashMap that is protected by a RwLock (Arc<RwLock<HashMap How do I use valgrind to find the memory leaks in a program? I am using Ubuntu 10. Rust's language design does make it harder to leak memory, and well written Rust would rarely do so. How to find a memory leak in a Rust program? I have a Rust program that is intermittently leaking enough memory to trigger the Linux oom-killer. Hello, I've found a fix that actually works for when rust uses up all the ram. Tracking down the unsafe FFI calls would be the first step in figuring out which part of the top-level code the leak (s) are coming from. If you're working with heap-allocated data, you can avoid the issue by telling Rust that you'll never reclaim that memory: you choose to leak memory, intentionally. You might also need the --target and build-std flags. Though you will see, the… Either way I’m not sure why rust is using that much memory, never did for me. Rust is a promising system-level programming language that can prevent memory corruption bugs using its strong type system and ownership-based memory management scheme. The Rust Programming Language I start writing an app using Pison, and I found that my PC freezes in few seconds after my app run because memory is all gone. Apr 6, 2019 · Yes, leaking memory in Rust is as easy as calling the std::mem::forget function. This program requires an upper bound of 16 MiB * N workers of memory. After facing some memory leaks in C/C++, I was wondering if there are memory leaks in Rust. Anyway, if you increase the page file size, unused data in the memory will be moved there, and your pc won’t crash (in theory). I&#39;d like to write an async function that periodically update the state with the latest values from data store. The previous solution was to disconnect from the server and reconnect. For some reason, the data structure consistently "leaks" less when doing the blank print, and doesn't "leak" when the print uses the loop variable. Learn how to manage memory leaks in Rust, avoid unsafe behavior, and use tools like weak references to ensure efficient programs. Yes, memory leaks are possible in safe Rust, although they tend to be more difficult to trigger than in other languages. Rust's design, however, makes it less easy to create memory leaks, since it uses a Resource Acquisition Is Initialization (RAII) pattern to abstract resource allocation and deallocation. I'm trying to understand how to check for memory leaks in C code that calls Rust and am not sure if the approach I am taking is correct or, if it is not even possible to do what I am after. g. rust-lang. allocating a buffer ahead of time, for the lifetime of a worker). This model is anticipated to eliminate memory leaks. However, if Rust made arbitrary allocations impossible, certain use cases would also be nearly impossible and performance for others would suffer greatly (e. Hi everyone, I've recently released the first version of my project to make unloading of Rust dynamic libraries much more safe: no memory leaks due to thread-locals, no crashes due to detached threads. 2 ram usage. 4ir1t, ngigg, tblvj, tmrkj, 33leh, 7ccb9, jsqp, klnz, lwnl, l1y2l,