perf top breakage.

perf top breakage.

[Dave Jones]

On Fri, Mar 14, 2014 at 12:41:41PM -0700, Linus Torvalds wrote:
 > On Fri, Mar 14, 2014 at 12:32 PM, Linus Torvalds
 > <torvalds@linux-foundation.org> wrote:
 > >
 > > Hmm. Do you have CONFIG_KALLSYMS enabled?
 > 
 > Just to clarify. KALLSYMS is required to figure out the symbol
 > addresses on a kaslr system. There's no way to look them up in a
 > System.map file or the object file, since the addresses aren't going
 > to match.
 > 
 > Your symptoms really sound like you might not have KALLSYMS enabled.
 > 
 > I wonder if we have a "select KALLSYMS" as part of RANDOMIZE_BASE,
 > since you need it for debug messages too (random hex numbers aren't
 > too useful ;)

Ok, I've figured out the cause. kaslr is a red herring.

This works :

# su - root
$ tools/perf/perf top

This doesn't:

# sudo tools/perf/perf top

Neither does:

# su - root
$ sudo tools/perf/perf top

So somehow sudo+perf broke. fun.

The 3.13 binary works regardless of how I call it.

	Dave