------- Comment From tmri...@de.ibm.com 2019-05-14 08:35 EDT------- I have debugged this issue Klaus reported.
I have installed the following system: root@s8360046:~/linux/tools/perf# uname -a Linux s8360046 4.18.0-17-generic #18-Ubuntu SMP Wed Mar 13 14:29:38 UTC 2019 s390x s390x s390x GNU/Linux root@s8360046:~/linux/tools/perf# and ran into the issue Klaus reported by running command root@s8360046:~/ # perf top in one window and in another window running this command while perf top was running: root@s8360046:~/ # for i in $(seq 15); do find / >/dev/null 2>&1; echo $i; done The issue shows up pretty quickly. I then cloned the linux kernel tree and build the perf tool from the downloaded linux kernel in directory linux/tools/perf. I did the same test with the locally compiled perf tools and the issue did not show up. To me it looked like the latest version did not have this problem. Next bisected the linux kernel tree (which also includes the perf tool) and the bisecting process stopped at the mentioned commit. Thats how I arrived at the commit id stated im comment 4. Obviously it did not fix the issue otherwise the patch would work. Sorry for that. It looks like we are back to start again. PS: I'm not sure but I have the feeling the issue only shows up when the debuginfo packages for the kernel are not installed. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1828166 Title: perf top problem on z with Ubuntu 18.04 Status in Ubuntu on IBM z Systems: In Progress Status in linux package in Ubuntu: Fix Released Status in linux source package in Bionic: In Progress Status in linux source package in Cosmic: In Progress Bug description: SRU Justification: ================== [Impact] * The perf top tool hangs and shows error messages, like 'Not enough memory for annotating' [Fix] * edeb0c90df3581b821a764052d185df985f8b8dc edeb0c9 "perf tools: Stop fallbacking to kallsyms for vdso symbols lookup" [Test Case] * start a benchmark (mem_alloc, but it doesn't really matter what) * execute perf top in a second terminal * the output of perf top is correct * now stop the benchmark * and perf top shows an error message, like "Not enough memory for annotating '__irf_end' symbol!)" * and perf top can't be exited anymore [Regression Potential] * The regression potential can be considered as low since this happens only while using the perf top tool * and it is known that the commit (above) fixes the problem * and the fix is upstream since 4.19 [Other Info] * current disco and eoan kernels don't show that problem * bisecting result points to above commit * applies cleanly on cosmic, but has a little conflict on bionic (both master-next) _________________________ perf top hangs and shows error messages ---uname output--- Linux weather 4.15.0-46-generic #49-Ubuntu SMP Wed Feb 6 09:32:27 UTC 2019 s390x s390x s390x GNU/Linux ---Steps to Reproduce--- I start a benchmark (mem_alloc, but it really doesn't matter) and then issue perf top in a second terminal, the output from perf top is correct. Now I stop the benchmark: perf top shows a error message (Not enough memory for annotating '__irf_end' symbol!) and I can't quit from perf top anymore Following analyse took place: No problem with current kernel . Bi-Secting of perf tool took place and following commit was found: commit edeb0c90df3581b821a764052d185df985f8b8dc (HEAD, refs/bisect/bad) Author: Arnaldo Carvalho de Melo <a...@redhat.com> Date: Tue Oct 16 17:08:29 2018 -0300 perf tools: Stop fallbacking to kallsyms for vdso symbols lookup When you apply this patch the issue is gone, however it is contained in these versions: git tag --contains edeb0c90df3581b821 v4.19 v4.20 .... The level I was debugging was kernel 4.15 which does not contain this patch. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-z-systems/+bug/1828166/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
