Previously, if unit_add_dependency_hashmap() failed, then a
one-directional unit dependency reference might be created, and
triggeres use-after-free. See issue #27742 for more details.
This makes unit dependency always bidirectional, and cleanly revert
partial update on failure.
Fixes#27742.
Previously, dependency chain of JoinsNamespaceOf= did not work, e.g.
- a.service has JoinsNamespaceOf=b.service
- b.service has JoinsNamespaceOf=c.service
if, first c.service, next a.service, finally b.service is started,
then a.service is not joined to the namespace of c.service. And, as
mentioned in the document, the namespace used by b.service is not
deterministic.
This makes when searching exsiting namespace to be joined, all units in
the transitive dependency of JoinsNamespaceOf= are checked.
Previously, even if a.service has JoinsNamespaceOf=b.service, the
inverse direction of reference was not introduced.
Hence, a.service is started earlier than b.service, the namespace will
not shared with b.service.
Also, even if a.service had the reference to b.service, b.service did not.
If b.service is freed earlier, then unit_clear_dependencies() does not clear
the reference from a to b, and will cause use-after-free on unit_free() for
a.service.
Let's make JoinsNamespaceOf=b.service in a.service implies the inverse
dependency, i.e. JoinsNamespaceOf=a.service for b.service. Then, we can safely
free b.service.
Let's explicitly order these against initrd-switch-root.target, so
that they are properly shut down before we switch root. Otherwise,
there's a race condition where networkd might only shut down after
switching root and after we've already we've loaded the unit graph,
meaning it won't be restarted in the rootfs.
Fixes#27718
Accel (Compute Acceleration) are new devices for AI/ML computation:
https://docs.kernel.org/accel/introduction.html
They are part of DRM subsystem. Add them to 'render' group since
no other appropriate group in standard linux systems exist. This
can be changed when proper common user-space components will emerge,
and new group for acceleration devices access will be established.
Signed-off-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Let's make the creds directories a bit more discoverable and make it
easier for users to use them. This also allows us to fix the
mode to 0700 for /etc instead of the usual 0755 which is what probably
would happen if users had to create this directory themselves.
