systemd System and Service Manager
+CHANGES WITH 247 in spe:
+
+ * KERNEL API INCOMPATIBILTY: Linux 4.12 introduced two new uevents
+ "bind" and "unbind" to the Linux device model. When this kernel
+ change was made, systemd-udevd was only minimally updated to handle
+ and propagate these new event types. The introduction of these new
+ uevents (which are typically generated for USB devices and devices
+ needing a firmware upload before being functional) resulted in a
+ number of software issues, we so far didn't address (mostly because
+ there was hope the kernel maintainers would themeselves address these
+ issues in some form – which did not happen). To handle them properly,
+ many (if not most) udev rules files shipped in various packages need
+ updating, and so do many programs that monitor or enumerate devices
+ with libudev or sd-device, or otherwise process uevents. Please note
+ that this incompatibility is not fault of systemd or udev, but caused
+ by an incompatible kernel change that happened back in Linux 4.12.
+
+ To minimize issues resulting from this kernel change (but not avoid
+ them entirely) starting with systemd-udevd 247 the udev "tags"
+ concept (which is a concept for marking and filtering devices during
+ enumeration and monitoring) has been reworked: udev tags are now
+ "sticky", meaning that once a tag is assigned to a device it will not
+ be removed from the device again until the device itself is removed
+ (i.e. unplugged). This makes sure that any application monitoring
+ devices that match a specific tag is guaranteed to both see uevents
+ where the device starts being relevant, and those where it stops
+ being relevant (the latter now regularly happening due to the new
+ "unbind" uevent type). The udev tags concept is hence now a concept
+ tied to a *device* instead of a device *event* — unlike for example
+ udev properties whose lifecycle (as before) is generally tied to a
+ device event, meaning that the previously determined properties are
+ forgotten whenever a new uevent is processed.
+
+ With the newly redefined udev tags concept, sometimes it's necessary
+ to determine which tags are the ones applied by the most recent
+ uevent/database update, in order to discern them from those
+ originating from earlier uevents/database updates of the same
+ device. To accommodate for this a new automatic property CURRENT_TAGS
+ has been added that works similar to the existing TAGS property but
+ only lists tags set by the most recent uevent/database
+ update. Similar, the libudev/sd-device API has been updated with new
+ functions to enumerate these 'current' tags, in addition to the
+ existing APIs that now enumerate the 'sticky' ones.
+
+ To properly handle "bind"/"unbind" on Linux 4.12 and newer it is
+ essential that all udev rules files and applications are updated to
+ handle the new events. Specifically:
+
+ • All rule files that currently use a header guard similar to
+ ACTION!="add|change",GOTO="xyz_end" should be updated to use
+ ACTION=="remove",GOTO="xyz_end" instead, so that the
+ properties/tags they add are also applied whenever "bind" (or
+ "unbind") is seen. (This is most important for all physical device
+ types — as that's for which "bind" and "unbind" are currently
+ usually generated, for all other device types this change is still
+ recommended but not as important — but certainly prepares for
+ future kernel uevent type additions).
+
+ • Similar, all code monitoring devices that contains an 'if' branch
+ discerning the "add" + "change" uevent actions from all other
+ uevents actions (i.e. considering devices only relevant after "add"
+ or "change", and irrelevant on all other events) should be reworked
+ to instead negatively check for "remove" only (i.e. considering
+ devices relevant after all event types, except for "remove", which
+ invalidates the device). Note that this also means that devices
+ should be considered relevant on "unbind", even though conceptually
+ this — in some form — invalidates the device. Since the precise
+ effect of "unbind" is not generically defined, devices should be
+ considered relevant even after "unbind", however I/O errors
+ accessing the device should then be handled gracefully.
+
+ • Any code that uses device tags for deciding whether a device is
+ relevant or not most likely needs to be updated to use the new
+ udev_device_has_current_tag() API (or sd_device_has_current_tag()
+ in case sd-device is used), to check whether the tag is set
+ at the moment an uevent is seen (as opposed to the existing
+ udev_device_has_tag() API which checks if the tag ever existed on
+ the device, following the API concept redefinition explained
+ above).
+
+ We are very sorry for this breakage and the requirement to update
+ packages using these interfaces. We'd again like to underline that
+ this is not caused by systemd/udev changes, but result of a kernel
+ behaviour change.
+
+ * Since PAM 1.2.0 (2015) configuration snippets may be placed in
+ /usr/lib/pam.d/ in addition to /etc/pam.d/. If a file exists in the
+ latter it takes precedence over the former, similar to how most of
+ systemd's own configuration is handled. Given that PAM stack
+ definitions are primarily put together by OS vendors/distributions
+ (though possibly overridden by users), this systemd release moves its
+ own PAM stack configuration for the "systemd-user" PAM service (i.e.
+ for the PAM session invoked by the per-user user@.service instance)
+ from /etc/pam.d/ to /usr/lib/pam.d/. We recommend moving all
+ packages' vendor versions of their PAM stack definitions from
+ /etc/pam.d/ to /usr/lib/pam.d/, but if such OS-wide migration is not
+ desired the location to which systemd installs its PAM stack
+ configuration file may be changed via the "pamconfdir" meson variable
+ at build time, optionally undoing this change of default paths
+ introduced with systemd 247.
+
CHANGES WITH 246:
* The service manager gained basic support for cgroup v2 freezer. Units
read and even write access to all these otherwise unmappable files,
which is quite likely a major security problem.
+ * tmpfs mounts automatically created by systemd (/tmp, /run, /dev/shm,
+ and others) now have a size and inode limits applied (50% of RAM for
+ /tmp and /dev/shm, 10% of RAM for other mounts, etc.). Please note
+ that the implicit kernel default is 50% too, so there is no change
+ in the size limit for /tmp and /dev/shm.
+
* nss-mymachines lost support for resolution of users and groups, and
now only does resolution of hostnames. This functionality is now
provided by nss-systemd. Thus, the 'mymachines' entry should be
now automatically set to "Y" at boot, in order to enable pstore
generation for collection with systemd-pstore.
- * A new 'hwdb' file has been added that collects information about PCI
- and USB devices that correctly support auto-suspend, on top of the
- databases for this we import from the ChromiumOS project. If you have
- a device that supports auto-suspend correctly and where it should be
- enabled by default, please submit a patch that adds it to the
- database (see /usr/lib/udev/hwdb.d/60-autosuspend.hwdb).
+ * We provide a set of udev rules to enable auto-suspend on PCI and USB
+ devices that were tested to correctly support it. Previously, this
+ was distributed as a set of udev rules, but has now been replaced by
+ by a set of hwdb entries (and a much shorter udev rule to take action
+ if the device modalias matches one of the new hwdb entries).
+
+ As before, entries are periodically imported from the database
+ maintained by the ChromiumOS project. If you have a device that
+ supports auto-suspend correctly and where it should be enabled by
+ default, please submit a patch that adds it to the database (see
+ /usr/lib/udev/hwdb.d/60-autosuspend.hwdb).
* systemd-udevd gained the new configuration option timeout_signal= as well
as a corresponding kernel command line option udev.timeout_signal=.
new boolean setting Assign=. If enabled an address from the prefix is
automatically assigned to the interface.
- * systemd-networkd's [Network] section gained a new setting
- IPv6PDSubnetId= that allows explicit configuration of the preferred
- subnet that networkd's Prefix Delegation logic assigns to interfaces.
+ * systemd-networkd gained a new section [DHCPv6PrefixDelegation] which
+ controls delegated prefixes assigned by DHCPv6 client. The section
+ has three settings: SubnetID=, Assign=, and Token=. The setting
+ SubnetID= allows explicit configuration of the preferred subnet that
+ systemd-networkd's Prefix Delegation logic assigns to interfaces. If
+ Assign= is enabled (which is the default) an address from any acquired
+ delegated prefix is automatically chosen and assigned to the
+ interface. The setting Token= specifies an optional address generation
+ mode for Assign=.
* systemd-networkd's [Network] section gained a new setting
IPv4AcceptLocal=. If enabled the interface accepts packets with local
interface which is fully set up for host communication, simply by
carefully picking an interface name to use.
- * A new boolean option AssignAcquiredDelegatedPrefixAddress= has been
- added to the [DHCPv6] section of .network files. If enabled (which is
- the default) an address from any acquired delegated prefix is
- automatically chosen and assigned to the interface.
-
* systemd-networkd's [DHCPv6] section gained a new setting RouteMetric=
which sets the route priority for routes specified by the DHCP server.
distribution-specific defaults in .mkosi/ based on your preference.
Contributions from: 24bisquitz, Adam Nielsen, Alan Perry, Alexander
- Malafeev, Alin Popa, Alvin Šipraga, Amos Bird, Andreas Rammhold,
- AndreRH, Andrew Doran, Anita Zhang, Ankit Jain, antznin, Arnaud
- Ferraris, Arthur Moraes do Lago, Arusekk, Balaji Punnuru, Balint
- Reczey, Bastien Nocera, bemarek, Benjamin Berg, Benjamin Dahlhoff,
- Benjamin Robin, Chris Down, Chris Kerr, Christian Göttsche, Christian
- Hesse, Christian Oder, Ciprian Hacman, Clinton Roy, codicodi, Corey
- Hinshaw, Daan De Meyer, Dana Olson, Dan Callaghan, Daniel Fullmer,
- Daniel Rusek, Dan Streetman, Dave Reisner, David Edmundson, David Wood,
- Denis Pronin, Diego Escalante Urrelo, Dimitri John Ledkov,
- dolphrundgren, duguxy, Einsler Lee, Elisei Roca, Emmanuel Garette, Eric
- Anderson, Eric DeVolder, Evgeny Vereshchagin, ExtinctFire, fangxiuning,
- Ferran Pallarès Roca, Filipe Brandenburger, Filippo Falezza, Finn,
- Florian Klink, Florian Mayer, Franck Bui, Frantisek Sumsal, gaurav,
- Georg Müller, Gergely Polonkai, Giedrius Statkevičius, Gigadoc2,
- gogogogi, gzjsgdsb, Hans de Goede, Haochen Tong, ianhi, ignapk, Jakov
- Smolic, James T. Lee, Jan Janssen, Jan Klötzke, Jan Palus, Jay Burger,
- Jeremy Cline, Jérémy Rosen, Jian-Hong Pan, Jiri Slaby, Joel Shapiro,
- Joerg Behrmann, Jörg Thalheim, Jouke Witteveen, Kai-Heng Feng, Kenny
- Levinsen, Kevin Kuehler, Kumar Kartikeya Dwivedi, layderv, laydervus,
- Lénaïc Huard, Lennart Poettering, Lidong Zhong, Luca Boccassi, Luca
- BRUNO, Lucas Werkmeister, Lukas Klingsbo, Lukáš Nykrýn, Łukasz
- Stelmach, Maciej S. Szmigiero, MadMcCrow, Marc-André Lureau, Marcel
- Holtmann, Marc Kleine-Budde, Martin Hundebøll, Matthew Leeds, Matt
- Ranostay, Maxim Fomin, MaxVerevkin, Michael Biebl, Michael Chapman,
- Michael Gubbels, Michael Marley, Michał Bartoszkiewicz, Michal Koutný,
- Michal Sekletár, Mike Gilbert, Mike Kazantsev, Mikhail Novosyolov, ml,
- Motiejus Jakštys, nabijaczleweli, nerdopolis, Niccolò Maggioni, Niklas
- Hambüchen, Norbert Lange, Paul Cercueil, pelzvieh, Peter Hutterer,
- Piero La Terza, Pieter Lexis, Piotr Drąg, Rafael Fontenelle, Richard
- Petri, Ronan Pigott, Ross Lagerwall, Rubens Figueiredo, satmandu,
- Sean-StarLabs, Sebastian Jennen, sterlinghughes, Surhud More, Susant
- Sahani, szb512, Thomas Haller, Tobias Hunger, Tom, Tomáš Pospíšek,
- Tomer Shechner, Tom Hughes, Topi Miettinen, Tudor Roman, Uwe
- Kleine-König, Valery0xff, Vito Caputo, Vladimir Panteleev, Vladyslav
- Tronko, Wen Yang, Yegor Vialov, Yigal Korman, Yi Gao, YmrDtnJu, Yuri
- Chornoivan, Yu Watanabe, Zbigniew Jędrzejewski-Szmek, Zhu Li, Дамјан
- Георгиевски, наб
-
- – Warsaw, 2020-07-24
+ Malafeev, Amitanand.Chikorde, Alin Popa, Alvin Šipraga, Amos Bird,
+ Andreas Rammhold, AndreRH, Andrew Doran, Anita Zhang, Ankit Jain,
+ antznin, Arnaud Ferraris, Arthur Moraes do Lago, Arusekk, Balaji
+ Punnuru, Balint Reczey, Bastien Nocera, bemarek, Benjamin Berg,
+ Benjamin Dahlhoff, Benjamin Robin, Chris Down, Chris Kerr, Christian
+ Göttsche, Christian Hesse, Christian Oder, Ciprian Hacman, Clinton Roy,
+ codicodi, Corey Hinshaw, Daan De Meyer, Dana Olson, Dan Callaghan,
+ Daniel Fullmer, Daniel Rusek, Dan Streetman, Dave Reisner, David
+ Edmundson, David Wood, Denis Pronin, Diego Escalante Urrelo, Dimitri
+ John Ledkov, dolphrundgren, duguxy, Einsler Lee, Elisei Roca, Emmanuel
+ Garette, Eric Anderson, Eric DeVolder, Evgeny Vereshchagin,
+ ExtinctFire, fangxiuning, Ferran Pallarès Roca, Filipe Brandenburger,
+ Filippo Falezza, Finn, Florian Klink, Florian Mayer, Franck Bui,
+ Frantisek Sumsal, gaurav, Georg Müller, Gergely Polonkai, Giedrius
+ Statkevičius, Gigadoc2, gogogogi, Gaurav Singh, gzjsgdsb, Hans de
+ Goede, Haochen Tong, ianhi, ignapk, Jakov Smolic, James T. Lee, Jan
+ Janssen, Jan Klötzke, Jan Palus, Jay Burger, Jeremy Cline, Jérémy
+ Rosen, Jian-Hong Pan, Jiri Slaby, Joel Shapiro, Joerg Behrmann, Jörg
+ Thalheim, Jouke Witteveen, Kai-Heng Feng, Kenny Levinsen, Kevin
+ Kuehler, Kumar Kartikeya Dwivedi, layderv, laydervus, Lénaïc Huard,
+ Lennart Poettering, Lidong Zhong, Luca Boccassi, Luca BRUNO, Lucas
+ Werkmeister, Lukas Klingsbo, Lukáš Nykrýn, Łukasz Stelmach, Maciej
+ S. Szmigiero, MadMcCrow, Marc-André Lureau, Marcel Holtmann, Marc
+ Kleine-Budde, Martin Hundebøll, Matthew Leeds, Matt Ranostay, Maxim
+ Fomin, MaxVerevkin, Michael Biebl, Michael Chapman, Michael Gubbels,
+ Michael Marley, Michał Bartoszkiewicz, Michal Koutný, Michal Sekletár,
+ Mike Gilbert, Mike Kazantsev, Mikhail Novosyolov, ml, Motiejus Jakštys,
+ nabijaczleweli, nerdopolis, Niccolò Maggioni, Niklas Hambüchen, Norbert
+ Lange, Paul Cercueil, pelzvieh, Peter Hutterer, Piero La Terza, Pieter
+ Lexis, Piotr Drąg, Rafael Fontenelle, Richard Petri, Ronan Pigott, Ross
+ Lagerwall, Rubens Figueiredo, satmandu, Sean-StarLabs, Sebastian
+ Jennen, sterlinghughes, Surhud More, Susant Sahani, szb512, Thomas
+ Haller, Tobias Hunger, Tom, Tomáš Pospíšek, Tomer Shechner, Tom Hughes,
+ Topi Miettinen, Tudor Roman, Uwe Kleine-König, Valery0xff, Vito Caputo,
+ Vladimir Panteleev, Vladyslav Tronko, Wen Yang, Yegor Vialov, Yigal
+ Korman, Yi Gao, YmrDtnJu, Yuri Chornoivan, Yu Watanabe, Zbigniew
+ Jędrzejewski-Szmek, Zhu Li, Дамјан Георгиевски, наб
+
+ – Warsaw, 2020-07-30
CHANGES WITH 245: