ACK/Cmnt: [SRU][Bionic][Cosmic][PATCH 0/1] Fix for perf top problem on s390x (LP: #1828166)

Connor Kuehl connor.kuehl at canonical.com
Fri May 10 16:46:54 UTC 2019


On 5/9/19 5:44 AM, Kleber Sacilotto de Souza wrote:
> BugLink: https://bugs.launchpad.net/1828166
> 
> [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"
> * The patch can be cleany applied to Cosmic but needed a simple
>   backport for Bionic for context adjustment.
> 
> [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
> 
> Arnaldo Carvalho de Melo (1):
>   perf tools: Stop fallbacking to kallsyms for vdso symbols lookup
> 
>  tools/perf/util/event.c | 21 ++-------------------
>  1 file changed, 2 insertions(+), 19 deletions(-)
> 

The BugLink will need to be adjusted slightly when this is applied to
have the '/bugs/' component:
https://bugs.launchpad.net/bugs/1828166

Otherwise it seems like a mature fix and the accompanying documentation
is thorough.

Acked-by: Connor Kuehl <connor.kuehl at canonical.com>
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