confusing but harmless warning messages printed about syscalls

Bug #1925216 reported by Dan Streetman
8
This bug affects 1 person
Affects Status Importance Assigned to Milestone
systemd (Ubuntu)
Undecided
Unassigned
Bionic
Low
Dan Streetman

Bug Description

[impact]

systemd prints messages that complain about system calls such as:

/lib/systemd/system/systemd-journald.service:33: Failed to parse system call, ignoring: pidfd_getfd

[test case]

boot bionic system with 4.15 kernel that does not support pidfd_getfd syscall

[regression potential]

any regression would prevent correct configuration of seccomp syscall filters, and/or failure to load/parse unit files that contain SystemCallFilter= directives

[scope]

this is needed only for b

this is fixed upstream by commit 13d92c6300edbb1369f97c2e1bef4c4096de8ddb which was included in v238, so this is fixed in focal and later

this is not needed for x as seccomp handling is completely different in that older release

[other info]

as the warning states, the invalid system call is ignored, which is the correct action, and the patch to fix this just changes the log to debug instead of warning (along with consolidation of several flag params into a single flag enum). Thus, no actual change in behavior should occur (other than logging the messages as debug instead of warning).

Also note that since this warning is the result of systemd's call into libseccomp2 to query the syscall, if libseccomp2 recognizes the syscall, the message will not be printed; the previous libseccomp2 for bionic (version 2.4.3) did not know the pidfd_getfd syscall, while the latest (version 2.5.1) does. So this is reproducable with libseccomp2 version 2.4.3 but not the latest 2.5.1.

Dan Streetman (ddstreet)
Changed in systemd (Ubuntu):
status: New → Fix Released
Changed in systemd (Ubuntu Bionic):
importance: Undecided → Low
Dan Streetman (ddstreet)
Changed in systemd (Ubuntu Bionic):
status: New → In Progress
assignee: nobody → Dan Streetman (ddstreet)
Revision history for this message
Brian Murray (brian-murray) wrote : Please test proposed package

Hello Dan, or anyone else affected,

Accepted systemd into bionic-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/systemd/237-3ubuntu10.48 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, what testing has been performed on the package and change the tag from verification-needed-bionic to verification-done-bionic. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-bionic. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance for helping!

N.B. The updated package will be released to -updates after the bug(s) fixed by this package have been verified and the package has been in -proposed for a minimum of 7 days.

Changed in systemd (Ubuntu Bionic):
status: In Progress → Fix Committed
tags: added: verification-needed verification-needed-bionic
Revision history for this message
Dan Streetman (ddstreet) wrote :

ubuntu@lp1925216-b:~$ dpkg -l |grep libseccomp2
ii libseccomp2:amd64 2.4.3-1ubuntu3.18.04.3 amd64 high level interface to Linux seccomp filter
ubuntu@lp1925216-b:~$ dpkg -l systemd|grep systemd
ii systemd 237-3ubuntu10.47 amd64 system and service manager
ubuntu@lp1925216-b:~$ journalctl -b | grep pidfd
Jun 04 14:24:47 lp1925216-b systemd[1]: /lib/systemd/system/systemd-journald.service:33: Failed to parse system call, ignoring: pidfd_getfd
Jun 04 14:24:47 lp1925216-b systemd[1]: /lib/systemd/system/systemd-timesyncd.service:41: Failed to parse system call, ignoring: pidfd_getfd
Jun 04 14:24:47 lp1925216-b systemd[1]: /lib/systemd/system/systemd-networkd.service:38: Failed to parse system call, ignoring: pidfd_getfd
Jun 04 14:24:47 lp1925216-b systemd[1]: /lib/systemd/system/systemd-resolved.service:42: Failed to parse system call, ignoring: pidfd_getfd
Jun 04 14:24:47 lp1925216-b systemd[1]: /lib/systemd/system/systemd-logind.service:35: Failed to parse system call, ignoring: pidfd_getfd
Jun 04 14:24:52 lp1925216-b systemd[1]: /lib/systemd/system/systemd-hostnamed.service:33: Failed to parse system call, ignoring: pidfd_getfd

ubuntu@lp1925216-b:~$ dpkg -l |grep libseccomp2
ii libseccomp2:amd64 2.4.3-1ubuntu3.18.04.3 amd64 high level interface to Linux seccomp filter
ubuntu@lp1925216-b:~$ dpkg -l systemd|grep systemd
ii systemd 237-3ubuntu10.48 amd64 system and service manager
ubuntu@lp1925216-b:~$ journalctl -b | grep pidfd
ubuntu@lp1925216-b:~$

description: updated
tags: added: verification-done verification-done-bionic
removed: verification-needed verification-needed-bionic
Revision history for this message
Brian Murray (brian-murray) wrote : Update Released

The verification of the Stable Release Update for systemd has completed successfully and the package is now being released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regressions.

Revision history for this message
Launchpad Janitor (janitor) wrote :

This bug was fixed in the package systemd - 237-3ubuntu10.48

---------------
systemd (237-3ubuntu10.48) bionic; urgency=medium

  * d/p/lp1925216-seccomp-rework-functions-for-parsing-system-call-fil.patch:
    Downgrade syscall group parsing failure logs to debug (LP: #1925216)
    https://git.launchpad.net/~ubuntu-core-dev/ubuntu/+source/systemd/commit/?id=8c0181e24f7c0128a48c706d1f4b28ec0f225fd7
  * d/p/lp1929560-network-move-set-MAC-and-set-nomaster-operations-out.patch:
    Move link mac and master config out of link_up() (LP: #1929560)
    https://git.launchpad.net/~ubuntu-core-dev/ubuntu/+source/systemd/commit/?id=d808ea22366ca7ba4b5bb32815ab0ca2eea8a49f
  * d/p/resolved-Mitigate-DVE-2018-0001-by-retrying-NXDOMAIN-with.patch,
    d/p/resolved_disable-connection-downgrade-when-DNSSEC-yes.patch,
    d/p/lp1880258-log-nxdomain-as-debug.patch,
    d/p/lp1785383-resolved-address-DVE-2018-0001.patch:
    - Use upstream patch for DVE-2018-0001 handling (LP: #1785383)
    https://git.launchpad.net/~ubuntu-core-dev/ubuntu/+source/systemd/commit/?id=b6258fda64c84c34b0f8026e6e29bcfffa8dc4f1

 -- Dan Streetman <email address hidden> Thu, 27 May 2021 11:18:38 -0400

Changed in systemd (Ubuntu Bionic):
status: Fix Committed → Fix Released
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