With cgroup v2 the cgroup freezer is implemented as a cgroup
attribute called cgroup.freeze. cgroup can be frozen by writing "1"
to the file and kernel will send us a notification through
"cgroup.events" after the operation is finished and processes in the
cgroup entered quiescent state, i.e. they are not scheduled to
run. Writing "0" to the attribute file does the inverse and process
execution is resumed.
This commit exposes above low-level functionality through systemd's DBus
API. Each unit type must provide specialized implementation for these
methods, otherwise, we return an error. So far only service, scope, and
slice unit types provide the support. It is possible to check if a
given unit has the support using CanFreeze() DBus property.
Note that DBus API has a synchronous behavior and we dispatch the reply
to freeze/thaw requests only after the kernel has notified us that
requested operation was completed.
It's not that I think that "hostname" is vastly superior to "host name". Quite
the opposite — the difference is small, and in some context the two-word version
does fit better. But in the tree, there are ~200 occurrences of the first, and
>1600 of the other, and consistent spelling is more important than any particular
spelling choice.
Hiding the first column, which may contain bullet circles, with --no-legend
is undocumented and potentially unexpected. On the other hand, not printing
bullet circles with --plain is documented so hiding the column with that
switch is sensible.
The combination "--full --no-legend --no-pager --plain" is appropriate for
automated processing of systemctl output.
Right now the kernel will not dump anything that went through setuid or
setgid. But it is routine for daemons to do that, and it makes things hard to
debug.
systemd-coredump saves the coredump readable by the users the process was
running as. This should be enough to avoid information leakage. So let's also
tell the kernel to do the coredump.
For https://bugzilla.redhat.com/show_bug.cgi?id=1790972.
Both patterns are stored in the same file, so they are enabled or disabled
together. (Though suid_dumpable=2 is supposed to be safe even when writing to
plain files.)
This never made into a release, so we can change the name with impunity.
Suggested by Davide Pesavento.
I opted to add the "ing" ending. "Fair queuing" is the name of the general
concept and algorithm, and "Fair queue" is mostly used for the implementation
name.
This makes the naming more consistent: we now have
bootctl systemd-efi-options,
$SYSTEMD_EFI_OPTIONS
and the SystemdOptions EFI variable.
(SystemdEFIOptions would be redundant, because it is only used in the context
of efivars, and users don't interact with that name directly.)
bootctl is adjusted to use 2sp indentation, similarly to systemctl and other
programs.
Remove the prefix with the old name from 'bootctl systemd-efi-options' output,
since it's redundant and we don't want the old name anyway.
On some systems with lots of devices, device probing for certain drivers can
take a very long time. If systemd-udevd detects a timeout and kills the worker
running modprobe using SIGKILL, some devices will not be probed, or end up in
unusable state. The --event-timeout option can be used to modify the maximum
time spent in an uevent handler. But if systemd-udevd exits, it uses a
different timeout, hard-coded to 30s, and exits when this timeout expires,
causing all workers to be KILLed by systemd afterwards. In practice, this may
lead to workers being killed after significantly less time than specified with
the event-timeout. This is particularly significant during initrd processing:
systemd-udevd will be stopped by systemd when initrd-switch-root.target is
about to be isolated, which usually happens quickly after finding and mounting
the root FS.
If systemd-udevd is started by PID 1 (i.e. basically always), systemd will
kill both udevd and the workers after expiry of TimeoutStopSec. This is
actually better than the built-in udevd timeout, because it's more transparent
and configurable for users. This way users can avoid the mentioned boot problem
by simply increasing StopTimeoutSec= in systemd-udevd.service.
If udevd is not started by systemd (standalone), this is still an
improvement. udevd will kill hanging workers when the event timeout is
reached, which is configurable via the udev.event_timeout= kernel
command line parameter. Before this patch, udevd would simply exit with
workers still running, which would then become zombie processes.
With the timeout removed, the sd_event_now() assertion in manager_exit() can be
dropped.
Discussed in #13743, the -.service semantic conflicts with the
existing root mount and slice names, making this feature not
uniformly extensible to all types. Change the name to be
<type>.d instead.
Updating to this format also extends the top-level dropin to
unit types.
I think we can mention that systemd-resolved is able to validate IP
address certificates and prefer TLS 1.3 before TLS 1.2 now.
Also the `machinectl reboot` command actually works now.
Signed-off-by: Christian Rebischke <chris@nullday.de>
In the past, we asked people to open a security bug on one of the "big"
distros. This worked OK as far as getting bugs reported and notifying some
upstream developers went. But we always had trouble getting information to
all the appropriate parties, because each time a bug was reported, a big
thread was created, with a growing CC list. People who were not CCed early
enough were missing some information, etc.
To clean this up, we decided to create a private mailing list. The natural
place would be freedesktop.org, but unfortunately the request to create a
mailing list wasn't handled
(https://gitlab.freedesktop.org/freedesktop/freedesktop/issues/134). And even
if it was, at this point, if there was ever another administrative issue, it
seems likely it could take months to resolve. So instead, we asked for a list
to be created on the redhat mailservers.
Please consider the previous security issue reporting mechanisms rescinded, and
send any senstive bugs to systemd-security@redhat.com.
Zbigniew Jędrzejewski-Szmek