# Capability Management **URL:** \ **Category:** Developer's Corner\ **Created:** [May 25, 2025, 12:27pm UTC](https://genode.discourse.group/t/capability-management/176 "2025-05-25T12:27:56Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![hamed](https://avatars.discourse-cdn.com/v4/letter/h/d6d6ee/32.png) [@hamed](https://genode.discourse.group/u/hamed)\ **Post date:** [May 25, 2025, 12:27pm UTC](https://genode.discourse.group/t/capability-management/176/1 "2025-05-25T12:27:56Z")
I’ve connected two components using the reporter mechanism and attach\_rom\_dataspace to transmit signals along with a small amount of associated data. After running for some time, the system reports the following error: request resources: cap\_quota=4. Is there a more efficient or recommended way within Genode to transmit lightweight data alongside a signal? and Should capabilities be explicitly released after use in this context, or is their accumulation an expected behavior governed by the framework’s internal resource management policy? ---
**Author:** ![ttcoder](https://dub1.discourse-cdn.com/flex006/user_avatar/genode.discourse.group/ttcoder/32/9_2.png) [@ttcoder](https://genode.discourse.group/u/ttcoder)\ **Post date:** [May 25, 2025, 1:17pm UTC](https://genode.discourse.group/t/capability-management/176/2 "2025-05-25T13:17:07Z")
Typically you’d instantiate the attached\_rom, then use that during the app’s lifetime, then free it when the app tears down, freeing the used capability. If the app is leaking caps, then 1.you could try to self-diagnose by sprinkling your code with “Genode::log( env.used\_caps()… )” statements, to determine who/where is increasing the used capbabilities count, or 2. post the code here so that we can review it I don’t remember seeing Genode leak caps by itself in my experiments (except a few years ago when calling pthread\_create() but the culprit might have been me), so it should be relatively easy to find out what’s going on, if you create a minimum reproducible case 🙂 ---
**Author:** ![chelmuth](https://dub1.discourse-cdn.com/flex006/user_avatar/genode.discourse.group/chelmuth/32/1_2.png) [@chelmuth](https://genode.discourse.group/u/chelmuth)\ **Post date:** [May 26, 2025, 6:38am UTC](https://genode.discourse.group/t/capability-management/176/3 "2025-05-26T06:38:22Z")
Does your reported data exceed the initial page-sized buffer at some point in time? ---
**Author:** ![hamed](https://avatars.discourse-cdn.com/v4/letter/h/d6d6ee/32.png) [@hamed](https://genode.discourse.group/u/hamed)\ **Post date:** [May 26, 2025, 7:06am UTC](https://genode.discourse.group/t/capability-management/176/4 "2025-05-26T07:06:14Z")
I’m using Genode’s native objects, specifically `Genode::Reporter` and `Genode::Attach_rom_dataspace`, so I would expect them to behave correctly. However, your point seems valid — I do use `pthread` in part of the code and interact with it. It appears that the target thread receives the signal but doesn’t release it afterward. Did I understand that correctly? ---
**Author:** ![hamed](https://avatars.discourse-cdn.com/v4/letter/h/d6d6ee/32.png) [@hamed](https://genode.discourse.group/u/hamed)\ **Post date:** [May 26, 2025, 7:08am UTC](https://genode.discourse.group/t/capability-management/176/5 "2025-05-26T07:08:28Z")
No, not at all. The data I report is usually just a few bytes, at most around 100 bytes. ---
**Author:** ![chelmuth](https://dub1.discourse-cdn.com/flex006/user_avatar/genode.discourse.group/chelmuth/32/1_2.png) [@chelmuth](https://genode.discourse.group/u/chelmuth)\ **Post date:** [May 26, 2025, 7:37am UTC](https://genode.discourse.group/t/capability-management/176/6 "2025-05-26T07:37:13Z")
For clarification: Are you implementing a component that uses libc (incl. pthreads) and runs out of resources (caps) at some point? Do you utilize dynamic memory allocation in the libc? RAM-Dataspaces also require cap quota as these are remote objects in core. ---
**Author:** ![hamed](https://avatars.discourse-cdn.com/v4/letter/h/d6d6ee/32.png) [@hamed](https://genode.discourse.group/u/hamed)\ **Post date:** [May 27, 2025, 5:44am UTC](https://genode.discourse.group/t/capability-management/176/7 "2025-05-27T05:44:53Z")
I was testing Genode’s notification mechanism within Qt5-based applications. My initial challenge was that notifications weren’t being received, which I first resolved using the `pthread` approach. Later, I learned that it’s also possible to connect a Qt5 signal to a notification, so I explored both methods to better understand the underlying processes. I’m using `libc` to run Qt5, but I don’t perform any manual memory allocation—Qt5 handles all memory management internally. When using the `pthread` method, I encountered a capability leak issue. I’m now trying to identify the root cause of this leak. At first, I suspected it might be related to the `Genode::Attach_rom_dataspace` object. However, as soon as I came across the term `pthread` in @ttcoder’s previous replies, I realized the memory leak likely stems from my own implementation. I’m currently investigating the exact cause of the leak.