Fix to show correct error messages for $vars and $params because
those special variables requires debug information to find the
real variables or function parameters.
E.g. without this fix;
----
# perf probe -x /lib64/libc-2.23.so getaddrinfo \$params
Failed to write event: Invalid argument
Please upgrade your kernel to at least 3.14 to have access to feature $params
Error: Failed to add events.
----
Perf ends up with an error, but the message is not correct. With this
fix, perf shows correct error message as below.
----
# perf probe -x /lib64/libc-2.23.so getaddrinfo \$params
The /usr/lib64/libc-2.23.so file has no debug information.
Rebuild with -g, or install an appropriate debuginfo package.
Error: Failed to add events.
----
Reported-and-Tested-by: Arnaldo Carvalho de Melo <acme@kernel.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Hemant Kumar <hemant@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/146831787438.17065.6152436996780110699.stgit@devbox
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
f6eb0518f3