tracing: tprobe-events: Fix leakage of module refcount

tracing: tprobe-events: Fix leakage of module refcount

commit ac91052f0ae5be9e46211ba92cc31c0e3b0a933a upstream.

When enabling the tracepoint at loading module, the target module
refcount is incremented by find_tracepoint_in_module(). But it is
unnecessary because the module is not unloaded while processing
module loading callbacks.
Moreover, the refcount is not decremented in that function.
To be clear the module refcount handling, move the try_module_get()
callsite to trace_fprobe_create_internal(), where it is actually
required.

Link: https://lore.kernel.org/all/174182761071.83274.18334217580449925882.stgit@devnote2/
Fixes: 57a7e6de9e30 ("tracing/fprobe: Support raw tracepoints on future loaded modules")
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>