On Thu, 29 Jun 2017 00:13:24 +0530
"Naveen N. Rao" [off-list ref] wrote:

On 2017/06/28 11:16PM, Masami Hiramatsu wrote:

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diff --git 

a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_eventname.tc 
b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_eventname.tc
new file mode 100644
index 0000000..d259031

--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_eventname.tc

@@ -0,0 +1,28 @@
+#!/bin/sh
+# description: Kprobe event auto/manual naming
+
+disable_events
+echo > kprobe_events
+
+:;: "Add an event on function without name" ;:
+
+FUNC=`grep -m 10 " [tT] [^.]*$" /proc/kallsyms | tail -n 1 | cut -f 3 -d " "`

On powerpc, this always ends up using a blacklisted function. So, I 
think we need a way to find a function that is not black listed.  

Hmm, if we increase the -m argument, like -m 100, is that still
in a blacklisted function?

Yes, most of the initial symbols are exception vectors which are 
blacklisted.

Hmm, then how about this? :)

grep _stext -A 1000 | grep -m 10 " [tT] [^.]*$" /proc/kallsyms

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However, one of the issues is that debugfs does not show all the address 
ranges that are blacklisted. I am coming up with a way to address that 
and will post patches once I have it working.

Would you find that is only on powerpc or generic issue?

I meant the address _ranges_ that are blacklisted such as the ones with 
__kprobes annotation and __entry_text and so on.

I see, but we can also check the address by comparing the address
of symbols, which also can be retrieved from kallsyms.
Since the test case is also applied to stable kernel, I don't want
to make it depending on some special kernel tweaks.

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With those patches, we should be able to select symbols that are not 
blacklisted.

Or, maybe we can use generic function, like "schedule" or "vfs_read"
etc.

Yes, I think this will be good for the generic test, but may not help 
selecting a dot symbol on powerpc.

Right, and it depends on what gcc version and option is specified.
So, maybe we can skip the test if there is no such symbols.

I intended to test the symbols with some dot-suffix, but it seems
ppc64 has dot-started symbols, right? If there is no dot-suffixed
symbols, I think this test should skip the test case.

Thank you,



-- 
Masami Hiramatsu [off-list ref]