1 files changed, 27 insertions, 0 deletions

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 7694f3e59797..4dda4f60a2a9 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -576,6 +576,16 @@ static void ftrace_shutdown_replenish(void)
         ftrace_pages->next = (void *)get_zeroed_page(GFP_KERNEL);
 }
 
+static void print_ip_ins(const char *fmt, unsigned char *p)
+{
+        int i;
+
+        printk(KERN_CONT "%s", fmt);
+
+        for (i = 0; i < MCOUNT_INSN_SIZE; i++)
+                printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
+}
+
 static int
 ftrace_code_disable(struct dyn_ftrace *rec)
 {
@@ -590,6 +600,23 @@ ftrace_code_disable(struct dyn_ftrace *rec)
 
         failed = ftrace_modify_code(ip, call, nop);
         if (failed) {
+                switch (failed) {
+                case 1:
+                        WARN_ON_ONCE(1);
+                        pr_info("ftrace faulted on modifying ");
+                        print_ip_sym(ip);
+                        break;
+                case 2:
+                        WARN_ON_ONCE(1);
+                        pr_info("ftrace failed to modify ");
+                        print_ip_sym(ip);
+                        print_ip_ins(" expected: ", call);
+                        print_ip_ins(" actual: ", (unsigned char *)ip);
+                        print_ip_ins(" replace: ", nop);
+                        printk(KERN_CONT "\n");
+                        break;
+                }
+
                 rec->flags |= FTRACE_FL_FAILED;
                 return 0;
         }