genode/repos
Christian Helmuth abefca500b libc: fix deadlock in pthread_cond_timedwait/signal()
The deadlock occured with three concurrently running threads: two
waiters calling pthread_cond_timedwait() and one signaller calling
pthread_cond_signal().

If waiter W1 hits its timeout, the signaller may have called
pthread_cond_signal(), detected this waiter and posted the internal
'signal_sem' concurrently. Then, the signaller waits for 'handshake_sem'
to ensure the waiter got woken up.

Waiter W1 can't consume the 'signal_sem' post by
'sem_wait(&c->signal_sem)' because another waiter W2 may have consumed
the post already above in sem_wait/timedwait(). Waiting for a post on
'signal_sem' would block the waiter W1 in perfect deadlock with
signaller on 'handshake_sem'. As W1 also owns 'counter_mutex' in this
situation, waiter W2 would block when trying to aquire 'counter_mutex'
and can't resolve the situation.

So, W1 does nothing in this case and we accept the spurious wakeup on
next pthread_cond_wait/timedwait().
2020-10-09 13:35:56 +02:00
..
base timeout: rework timeout framework 2020-10-09 13:35:56 +02:00
base-fiasco depot: update recipe hashes 2020-09-17 14:23:14 +02:00
base-foc core: store new affinity on successful migration 2020-10-09 13:33:36 +02:00
base-hw timeout: rework timeout framework 2020-10-09 13:35:56 +02:00
base-linux linux: round up dataspace to 4k sizes 2020-10-09 13:35:55 +02:00
base-nova timeout: rework timeout framework 2020-10-09 13:35:56 +02:00
base-okl4 depot: update recipe hashes 2020-09-17 14:23:14 +02:00
base-pistachio core: store new affinity on successful migration 2020-10-09 13:33:36 +02:00
base-sel4 core: store new affinity on successful migration 2020-10-09 13:33:36 +02:00
dde_bsd depot: update recipe hashes 2020-09-17 14:23:14 +02:00
dde_ipxe depot: update recipe hashes 2020-09-17 14:23:14 +02:00
dde_linux timeout: rework timeout framework 2020-10-09 13:35:56 +02:00
dde_rump base: remove alarm library from base 2020-10-09 13:33:36 +02:00
demo depot: update recipe hashes 2020-09-17 14:23:14 +02:00
gems sculpt: version 20.09 2020-09-18 15:20:18 +02:00
hello_tutorial Add missing override annotations 2019-02-19 11:12:11 +01:00
libports libc: fix deadlock in pthread_cond_timedwait/signal() 2020-10-09 13:35:56 +02:00
os timeout: rework timeout framework 2020-10-09 13:35:56 +02:00
ports tool chain: fix build error on Ubuntu 20.04 (GCC 9) 2020-10-09 13:33:35 +02:00
README Remove dde_zircon 2020-08-25 11:49:44 +02:00

                      ===============================
                      Genode source-code repositories
                      ===============================


This directory contains the source-code repositories of the Genode OS
Framework. Each sub directory has the same principle layout as described in the
build-system manual:

:Build-system manual:

  [https://genode.org/documentation/developer-resources/build_system]

The build system uses a configurable selection of those reposities to obtain
the source codes for the build process. The repositories are not independent
but build upon of each other:

:'base':

  This directory contains the source-code repository of the fundamental
  frameworks and interfaces of Genode. Furthermore, it contains the generic
  parts of core.

:'base-<platform>':
  These directories contain platform-specific source-code repositories
  complementing the 'base' repository. The following platforms are supported:

  :'linux':
    Linux kernel (both x86_32 and x86_64)

  :'nova':
    NOVA hypervisor developed at University of Technology Dresden
    See [https://genode.org/documentation/platforms/nova]

  :'foc':
    Fiasco.OC is a modernized version of the Fiasco microkernel with a
    completely revised kernel interface fostering capability-based
    security. It is not compatible with L4/Fiasco.
    See [https://genode.org/documentation/platforms/foc]

  :'hw':
    The hw platform allows the execution of Genode on bare ARM and x86 hardware
    without the need for a separate kernel. The kernel functionality is
    included in core except in the special case of the Muen separation
    kernel.
    See [https://genode.org/documentation/platforms/hw] and
    [https://genode.org/documentation/platforms/muen]

  :'okl4':
    OKL4 kernel (x86_32 and ARM) developed at Open-Kernel-Labs.
    See [https://genode.org/documentation/platforms/okl4]

  :'pistachio':
    L4ka::Pistachio kernel developed at University of Karlsruhe.
    See [https://genode.org/documentation/platforms/pistachio]

  :'fiasco':
    L4/Fiasco kernel developed at University of Technology Dresden.
    See [https://genode.org/documentation/platforms/fiasco]

  :'sel4':
    seL4 microkernel developed at NICTA/General Dynamics
    See[https://sel4.systems/]

:'os':

  This directory contains the non-base OS components such as the init process,
  device drivers, and basic system services.

:'demo':

  This directory contains the source-code repository of various services and
  applications that we use for demonstration purposes. For example, a graphical
  application launcher called Launchpad and the Scout tutorial browser.

:'hello_tutorial':

  Tutorial for creating a simple client-server scenario with Genode. This
  repository includes documentation and the complete source code.

:'libports':

  This source-code repository contains ports of popular open-source libraries
  to Genode, most importantly the C library. The repository contains no
  upstream source code but means to download the code and adapt it to Genode.
  For instructions about how to use this mechanism, please consult the README
  file at the top level of the repository. Among the 3rd-party libraries
  are Qt5, libSDL, freetype, Python, ncurses, Mesa, and libav.

:'dde_linux':

  This source-code repository contains the device driver environment for
  executing Linux device drivers natively on Genode. Currently, this
  repository hosts the USB stack.

:'dde_ipxe':

  This source-code repository contains the device-driver environment for
  executing drivers of the iPXE project.

:'dde_bsd':

  This source-code repository contains the device-driver environment for
  drivers of the OpenBSD operating system.

:'dde_rump':

  This source-code repository contains the port of rump kernels, which are
  used to execute subsystems of the NetBSD kernel as user level processes.
  The repository contains a server that uses a rump kernel to provide
  various NetBSD file systems to Genode.

:'ports':

  This source-code repository hosts ports of 3rd-party applications to
  Genode. The repository does not contain upstream source code but provides
  a mechanism for downloading the official source distributions and adapt
  them to the Genode environment. The used mechanism is roughly the same
  as used for the 'libports' repository. Please consult 'libports/README'
  for further information.

:'gems':

  This source-code repository contains Genode applications that use
  both native Genode interfaces as well as features of other high-level
  repositories, in particular shared libraries provided by 'libports'.