[tip:perf/core] trace/kprobes: Add back warning about offset in return probes

["tip-bot for Steven Rostedt (VMware)" <tipbot@zytor.com>]

Commit-ID:  d0e02579c282ccf34c79818045ec2d2934b56c19
Gitweb:     http://git.kernel.org/tip/d0e02579c282ccf34c79818045ec2d2934b56c19
Author:     Steven Rostedt (VMware) <rostedt@goodmis.org>
AuthorDate: Mon, 27 Feb 2017 11:52:04 -0500
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Fri, 3 Mar 2017 19:07:19 -0300

trace/kprobes: Add back warning about offset in return probes

Let's not remove the warning about offsets and return probes when the
offset is invalid.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/20170227115204.00f92846@gandalf.local.home
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 kernel/trace/trace_kprobe.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 18775ef..2b7d0dd 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -695,6 +695,11 @@ static int create_trace_kprobe(int argc, char **argv)
 			pr_info("Failed to parse symbol.\n");
 			return ret;
 		}
+		if (offset && is_return &&
+		    !arch_function_offset_within_entry(offset)) {
+			pr_info("Given offset is not valid for return probe.\n");
+			return -EINVAL;
+		}
 	}
 	argc -= 2; argv += 2;