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
* 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, 10% of RAM for /dev/shm, etc.)
+ /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
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=.
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:
projects / thirdparty / systemd.git / blobdiff