commit 593eb8a2d63e95772a5f22d746f18a997c5ee463
author Steven Rostedt <rostedt@goodmis.org> Thu Oct 23 09:32:59 2008 -0400
committer Ingo Molnar <mingo@elte.hu> Thu Oct 23 16:00:13 2008 +0200
tree 2a99c61ccffc2c0fd280bb2e5f81ac2f22e2f471
parent 34698bcbdf7b0629d6c873b5da7c63073fb45361

ftrace: return error on failed modified text.

Have the ftrace_modify_code return error values:

  -EFAULT on error of reading the address

  -EINVAL if what is read does not match what it expected

  -EPERM  if the write fails to update after a successful match.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel/trace/ftrace.c

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 1f54a94..b2de8de 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -596,22 +596,22 @@
 {
 	unsigned long ip;
 	unsigned char *nop, *call;
-	int failed;
+	int ret;
 
 	ip = rec->ip;
 
 	nop = ftrace_nop_replace();
 	call = ftrace_call_replace(ip, mcount_addr);
 
-	failed = ftrace_modify_code(ip, call, nop);
-	if (failed) {
-		switch (failed) {
-		case 1:
+	ret = ftrace_modify_code(ip, call, nop);
+	if (ret) {
+		switch (ret) {
+		case -EFAULT:
 			WARN_ON_ONCE(1);
 			pr_info("ftrace faulted on modifying ");
 			print_ip_sym(ip);
 			break;
-		case 2:
+		case -EINVAL:
 			WARN_ON_ONCE(1);
 			pr_info("ftrace failed to modify ");
 			print_ip_sym(ip);
@@ -620,6 +620,15 @@
 			print_ip_ins(" replace: ", nop);
 			printk(KERN_CONT "\n");
 			break;
+		case -EPERM:
+			WARN_ON_ONCE(1);
+			pr_info("ftrace faulted on writing ");
+			print_ip_sym(ip);
+			break;
+		default:
+			WARN_ON_ONCE(1);
+			pr_info("ftrace faulted on unknown error ");
+			print_ip_sym(ip);
 		}
 
 		rec->flags |= FTRACE_FL_FAILED;