Messages in this thread | | | Date | Wed, 27 Nov 2013 10:18:22 +0200 | From | Adrian Hunter <> | Subject | Re: [PATCH] perf tools: Fix not finding kcore in buildid cache |
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On 26/11/13 18:15, Ingo Molnar wrote: > > * Adrian Hunter <adrian.hunter@intel.com> wrote: > >> The logic was not looking in the buildid cache for kcore >> if the host kernel buildid did not match the recorded >> kernel buildid. > > It would be nice to also include the specific failure mode in the > changelog: exactly how can users run into this. That will be more > useful to most people reading these changelogs than a more abstract > bug description.
The preconditions for the problem are that kcore is in the buildid cache and that the running kernel has a different buildid e.g.
$ perf buildid-list | grep kernel.kallsyms b18fbe769dea12513028a4287dae02efc1582c29 [kernel.kallsyms]
$ perf record -o /tmp/junk true >/dev/null 2>&1 ; perf buildid-list -i /tmp/junk | grep kernel.kallsyms 504f9fd9328c40714995ce76fe1354c6e90136ce [kernel.kallsyms]
Before the patch:
$ perf script -v >out.txt build id event received for [kernel.kallsyms]: b18fbe769dea12513028a4287dae02efc1582c29 <SNIP> Using /home/ahunter/.debug/[kernel.kallsyms]/b18fbe769dea12513028a4287dae02efc1582c29 for symbols
perf script stopped
After the patch:
$ perf script -v >out.txt build id event received for [kernel.kallsyms]: b18fbe769dea12513028a4287dae02efc1582c29 <SNIP> Using /home/ahunter/.debug/[kernel.kcore]/b18fbe769dea12513028a4287dae02efc1582c29/2013112617084061/kcore for kernel object code Using /home/ahunter/.debug/[kernel.kcore]/b18fbe769dea12513028a4287dae02efc1582c29/2013112617084061/kallsyms for symbols
perf script stopped
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