mirror of
https://github.com/genodelabs/genode.git
synced 2024-12-23 23:42:32 +00:00
Genode OS Framework
armcpluspluscppframeworkgenodegoahypervisorlinuxmicrokernelnovaobject-capabilitiesoperating-systemosdevriscvsculpt-ossel4virtualizationx86
53a990579b
This was discovered when building the code with clang instead of GCC. In this setup the run/ping on base-hw/arm_v8a/virt_qemu would crash on shutdown due to uncaught Deref_unconstructed_object exception thrown for Genode::Reconstructible<Genode::Account<Genode::Ram_quota>>. The specific instance throwing this exception was Pd_session_component::_ram_account. My investigation exposed the following problem: 1. The Pd_session_component has a _sliced_heap member backed by _constrained_ram_alloc which in turn uses Pd_session_component itself as its Ram_allocator. 2. When ~Pd_session_component is called it first destroys _ram_account, followed by _signal_broker. 3. The signal broker holds a reference to Pd_session_component::_sliced_heap as Signal_broker::_md_alloc. 4. The base-hw implementation of ~Signal_broker destroys some contexts and does this by calling Genode::destroy on some slabs using the _md_alloc (ref to Pd_session_component::_sliced_heap). 5. The Genode::Slab calls the Ram_allocator::free which ends up calling Pd_session_component::free. 6. The Pd_session_component::free can among other things call replenish method on Pd_session_component::_ram_account which has already been freed at this point. From my POV calling replenish at this point is basically an undefined behavior. The Genode::Constructible holding the Genode::Account was already detroyed at this point. GCC builds happen to somehow manage to go through the -> operator call without raising any alarms, while clang builds trip on the _check_constructed() call. This fix moves the _ram_account a bit higher in class declaration to ensure its destroyed after _sliced_heap. This seems like the simpliest solution for this problem. Fixes #3941 |
||
|---|---|---|
| depot | ||
| doc | ||
| repos | ||
| tool | ||
| .gitignore | ||
| LICENSE | ||
| README | ||
| VERSION | ||
=================================
Genode Operating System Framework
=================================
This is the source tree of the reference implementation of the Genode OS
architecture. For a general overview about the architecture, please refer to
the project's official website:
:Official project website for the Genode OS Framework:
[https://genode.org/documentation/general-overview]
The current implementation can be compiled for 8 different kernels: Linux,
L4ka::Pistachio, L4/Fiasco, OKL4, NOVA, Fiasco.OC, seL4, and a custom
kernel for running Genode directly on ARM-based hardware. Whereas the Linux
version serves us as development vehicle and enables us to rapidly develop the
generic parts of the system, the actual target platforms of the framework are
microkernels. There is no "perfect" microkernel - and neither should there be
one. If a microkernel pretended to be fit for all use cases, it wouldn't be
"micro". Hence, all microkernels differ in terms of their respective features,
complexity, and supported hardware architectures.
Genode allows the use of each of the kernels listed above with a rich set of
device drivers, protocol stacks, libraries, and applications in a uniform way.
For developers, the framework provides an easy way to target multiple different
kernels instead of tying the development to a particular kernel technology. For
kernel developers, Genode contributes advanced workloads, stress-testing their
kernel, and enabling a variety of application use cases that would not be
possible otherwise. For users and system integrators, it enables the choice of
the kernel that fits best with the requirements at hand for the particular
usage scenario.
Documentation
#############
The primary documentation is the book "Genode Foundations", which is available
on the front page of Genode website:
:Download the book "Genode Foundations":
[https://genode.org]
The book describes Genode in a holistic and comprehensive way. It equips you
with a thorough understanding of the architecture, assists developers with the
explanation of the development environment and system configuration, and
provides a look under the hood of the framework. Furthermore, it contains the
specification of the framework's programming interface.
The project has a quarterly release cycle. Each version is accompanied with
detailed release documentation, which is available at the documentation
section of the project website:
:Release documentation:
[https://genode.org/documentation/release-notes/]
Directory overview
##################
The source tree is composed of the following subdirectories:
:'doc':
This directory contains general documentation. Please consider the following
document for a quick guide to get started with the framework:
! doc/getting_started.txt
If you are curious about the ready-to-use components that come with the
framework, please review the components overview:
! doc/components.txt
:'repos':
This directory contains the so-called source-code repositories of Genode.
Please refer to the README file in the 'repos' directory to learn more
about the roles of the individual repositories.
:'tool':
Source-code management tools and scripts. Please refer to the README file
contained in the directory.
:'depot' and 'public':
Local depot and public archive of Genode packages. Please refer to
! doc/depot.txt
for more details.
Additional community-maintained components
##########################################
The components found within the main source tree are complemented by a growing
library of additional software, which can be seamlessly integrated into Genode
system scenarios.
:Genode-world repository:
[https://github.com/genodelabs/genode-world]
Contact
#######
The best way to get in touch with Genode developers and users is the project's
mailing list. Please feel welcome to join in!
:Genode Mailing Lists:
[https://genode.org/community/mailing-lists]
Commercial support
##################
The driving force behind the Genode OS Framework is the German company Genode
Labs. The company offers commercial licensing, trainings, support, and
contracted development work:
:Genode Labs website:
[https://www.genode-labs.com]