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>

1 files changed, 5 insertions, 0 deletions

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 18775ef182f8..2b7d0dd938ba 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;