Rocker Zhang
66a0bdad4f
During soft-reboot teardown, systemd-cryptsetup@.service's ExecStop runs
libcryptsetup's crypt_deactivate(), which issues DM_REMOVE with a udev
cookie and blocks in dm_udev_wait() until 95-dm-notify.rules decrements
the cookie semaphore via "dmsetup udevcomplete $env{DM_COOKIE}".
The generated cryptsetup unit had only After=systemd-udevd-kernel.socket,
not After=systemd-udevd.service. The .socket has IgnoreOnIsolate=yes and
is not stopped during soft-reboot, so it provides no ordering at all for
the service teardown. Meanwhile systemd-udevd.service has
Conflicts=soft-reboot.target (added in 0d1819e791) and stops as soon as
soft-reboot.target starts, with no ordering relative to cryptsetup's
ExecStop.
Once udevd's device monitor event source is disabled in manager_exit(),
pending DM_REMOVE uevents are no longer processed and the cookie
semaphore stays at 1 forever, blocking soft-reboot at "Stopping
Cryptography Setup..." until JobTimeoutSec=30min on soft-reboot.target
fires.
Add systemd-udevd.service to the After= ordering of the generated
cryptsetup, veritysetup and integritysetup units. By systemd's job
ordering rules (job_compare() in src/core/job.c), when two units are
both being stopped and one has After= the other, the After= unit is
stopped first. So with cryptsetup@*.service After=systemd-udevd.service,
cryptsetup stops first (cookie acknowledged by the still-live udevd),
then udevd stops.
Putting After=umount.target on systemd-udevd.service does not work: at
soft-reboot, udevd's stop job runs concurrently with umount.target's
start job, and JOB_STOP unconditionally precedes JOB_START in the
transaction (see src/core/job.c:1742). The ordering has to be expressed
between two stop jobs, which is what putting After=systemd-udevd.service
on the dm consumers achieves.
Fixes: #40298
System and Service Manager
Details
Most documentation is available on systemd's web site.
Assorted, older, general information about systemd can be found in the systemd Wiki.
Information about build requirements is provided in the README file.
Consult our NEWS file for information about what's new in the most recent systemd versions.
Please see the Code Map for information about this repository's layout and content.
Please see the Hacking guide for information on how to hack on systemd and test your modifications.
Please see our Contribution Guidelines for more information about filing GitHub Issues and posting GitHub Pull Requests.
When preparing patches for systemd, please follow our Coding Style Guidelines.
If you are looking for support, please contact our mailing list, join our IRC channel #systemd on libera.chat or Matrix channel
Stable branches with backported patches are available in the stable repo.
We have a security bug bounty program sponsored by the Sovereign Tech Fund hosted on YesWeHack
Repositories with distribution packages built from git main are available on OBS, and also repositories with packages built from the latest stable release