Ubuntu
systemtap package

Linux kernel > 4.14 requires systemtap 3.2

Bug #1766754 reported by paulcd2000
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
systemtap (Ubuntu)
Fix Released
High
Tyler Hicks

Bug Description

[Impact]

systemtap cannot be used in Ubuntu 18.04 due to kernel ABI incompatibilities with the 4.15 based kernel. The upstream kernel changes are:

- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7eeb6b893bd28c68b6d664de1d3120e49b855cdb
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d3a024abbc43827785

[Test Case]

Load an example systemtap script to verify that it can be built and used with the Ubuntu 18.04 kernel.

$ sudo stap -v -e 'probe kernel.function("proc_dostring") {printf("proc_dostring() called\n"); exit()}'

In another terminal, execute 'cat /proc/sys/kernel/hostname' and the stap command should print "proc_dostring() called" and exit. See the stap-bad.txt and stap-good.txt attachments for example output.

[Regression Potential]

Low regression potential since the package does not currently work as-is.

[Original Bug Report]

Per https://sourceware.org/bugzilla/show_bug.cgi?id=22158 , Systemtap 3.1 is broken on kernel versions > 4.14. It looks like they're aware of this in the debian package : https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=892995 . With Bionic Beaver about to ship with kernel 4.15 and systemtap 3.1-3, systemtap will be unusable on the LTS of Ubuntu.

$ lsb_release -rd
Description: Ubuntu Bionic Beaver (development branch)
Release: 18.04
$ uname -a
Linux appliance 4.15.0-19-generic #20-Ubuntu SMP Sun Apr 22 00:03:34 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
$ apt-cache policy systemtap
systemtap:
  Installed: 3.1-3
  Candidate: 3.1-3
  Version table:
 *** 3.1-3 500
        500 http://archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
        100 /var/lib/dpkg/status

See original description
paulcd2000 (paulcd2000)
description: updated
Revision history for this message
Tyler Hicks (tyhicks) wrote :

The Debian bug report mentions two upstream commits:

 https://sourceware.org/git/gitweb.cgi?p=systemtap.git;a=commitdiff;h=fbb26e17a
 https://sourceware.org/git/gitweb.cgi?p=systemtap.git;a=commitdiff;h=0643ca2b7

They both cherry-picked cleanly to the Bionic package so I prepared a test build of systemtap with those two patches applied in this PPA:

 https://launchpad.net/~tyhicks/+archive/ubuntu/testing/+packages

Please let me know if the new package works for you and we can start the process of getting the update into Ubuntu 18.04.

Tyler Hicks (tyhicks)
description: updated
description: updated
Revision history for this message
Tyler Hicks (tyhicks) wrote :

Here's the output from systemtap 3.1-3, under the Ubuntu 4.15.0-20.21-generic kernel, showing failure to build the module.

description: updated
Revision history for this message
Tyler Hicks (tyhicks) wrote :

Here's the output from systemtap 3.1-3 patched with the two upstream fixes mentioned in the [Impact] section, under the Ubuntu 4.15.0-20.21-generic kernel, showing success.

Revision history for this message
Tyler Hicks (tyhicks) wrote :

Sorry, the last comment was incorrect. The two upstream fixes are mentioned in comment #1, not the [Impact] section.

Tyler Hicks (tyhicks)
Changed in systemtap (Ubuntu):
importance: Undecided → High
status: New → In Progress
assignee: nobody → Tyler Hicks (tyhicks)
Revision history for this message
Tyler Hicks (tyhicks) wrote :

I tested systemtap 3.1-3ubuntu0.1 from bionic-proposed and have verified that it works as described in the [Test Case] section. Its output matches what I previously attached in stap-good.txt.

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

This bug was fixed in the package systemtap - 3.1-3ubuntu0.1

---------------
systemtap (3.1-3ubuntu0.1) bionic-proposed; urgency=medium

  * Fix errors seen with Bionic's 4.15 based kernel due to upstream
    kernel changes (LP: #1766754)
    - PR22158-Fix-missing-spin_unlock_wait-declaration.patch
    - PR22551-Fix-reworked-timer-usage.patch

 -- Tyler Hicks <email address hidden> Wed, 25 Apr 2018 20:56:22 +0000

Changed in systemtap (Ubuntu):
status: In Progress → Fix Released
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