+++ This bug was initially created as a clone of Bug #1386412 +++ Back in 2015, lttng-ust's fedora .spec file stopped building with systemtap's sys/sdt.h enablement. If there was no technical problem with it, please consider turning that back on. --- Additional comment from Fedora End Of Life on 2017-02-28 05:28:08 EST --- This bug appears to have been reported against 'rawhide' during the Fedora 26 development cycle. Changing version to '26'. --- Additional comment from Fedora End Of Life on 2018-05-03 04:24:40 EDT --- This message is a reminder that Fedora 26 is nearing its end of life. Approximately 4 (four) weeks from now Fedora will stop maintaining and issuing updates for Fedora 26. It is Fedora's policy to close all bug reports from releases that are no longer maintained. At that time this bug will be closed as EOL if it remains open with a Fedora 'version' of '26'. Package Maintainer: If you wish for this bug to remain open because you plan to fix it in a currently maintained version, simply change the 'version' to a later Fedora version. Thank you for reporting this issue and we are sorry that we were not able to fix it before Fedora 26 is end of life. If you would still like to see this bug fixed and are able to reproduce it against a later version of Fedora, you are encouraged change the 'version' to a later Fedora version prior this bug is closed as described in the policy above. Although we aim to fix as many bugs as possible during every release's lifetime, sometimes those efforts are overtaken by events. Often a more recent Fedora release includes newer upstream software that fixes bugs or makes them obsolete. --- Additional comment from Fedora End Of Life on 2018-05-29 07:37:32 EDT --- Fedora 26 changed to end-of-life (EOL) status on 2018-05-29. Fedora 26 is no longer maintained, which means that it will not receive any further security or bug fix updates. As a result we are closing this bug. If you can reproduce this bug against a currently maintained version of Fedora please feel free to reopen this bug against that version. If you are unable to reopen this bug, please file a new report against the current release. If you experience problems, please add a comment to this bug. Thank you for reporting this bug and we are sorry it could not be fixed. --- Additional comment from Frank Ch. Eigler on 2018-05-29 09:04:51 EDT --- lttng-ust-2.10.0 works fine on x86-64 f27 with --with-sdt on %configure. Please advise if you know of some reason not to turn this on. --- Additional comment from Michael Jeanson on 2018-05-29 13:49:45 EDT --- Hi, This feature was turned-off on a recommendation from the upstream developer. It's rarely used and adds a small performance hit to other more common use-cases. I'm open to re-enabling it if some users have a need for it. Regards, Michael --- Additional comment from Frank Ch. Eigler on 2018-05-29 15:24:32 EDT --- Can you advise how the performance hit was or could be measured? sys/sdt.h stuff costs only a single NOP in the lightweight use cases. A growing number of tools like perf, gdb, and a bunch of bpf-based ones, can be consumers of this data, so if the cost is negligible, even small benefits could justify turning this back on.
Hi Frank, is there anything we can do to test that it's fixed?
The easiest test is to run "readelf -n /path/to/binary" to see if any NT_STAPSDT (SystemTap probe descriptors) records show up. There should be at least one per STAP_PROBE* macro compiled into your shlib/binary.
Thank you @fche :]
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHBA-2018:1966