Messages in this thread | | | Date | Thu, 12 May 2011 23:38:37 +0200 | Subject | Re: [BUG] perf: bogus correlation of kernel symbols | From | Stephane Eranian <> |
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On Thu, May 12, 2011 at 11:35 PM, Ingo Molnar <mingo@elte.hu> wrote: > > * Stephane Eranian <eranian@google.com> wrote: > >> The other contradiction, I see, is that you have perf_event paranoia level >> and this new kptr masquerading feature which conflict with each >> other. >> >> You can be allowed to monitor at the kernel level (paranoid=1, default) >> but you cannot correlate symbols: >> >> $ perf record -e cycles:k foo >> >> I suspect if you have this kptr thing turned on, then you need to disallow >> monitoring at the kernel level too. > > The better (and consistent) solution would be to turn the kptr_restrict thing > off - see the patch i sent. > I saw that. But I think that when someone turns it back on, then you need to increase the perf_events paranoia level to disallow kernel monitoring to regular users such that you maintain consistency across the board.
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