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>
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 8821cea..4282915 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -62,7 +62,6 @@
unsigned char *new_code)
{
unsigned char replaced[MCOUNT_INSN_SIZE];
- int ret;
/*
* Note: Due to modules and __init, code can
@@ -72,15 +71,16 @@
* No real locking needed, this code is run through
* kstop_machine, or before SMP starts.
*/
- if (__copy_from_user_inatomic(replaced, (char __user *)ip, MCOUNT_INSN_SIZE))
- return 1;
+ if (__copy_from_user_inatomic(replaced, (char __user *)ip,
+ MCOUNT_INSN_SIZE))
+ return -EFAULT;
if (memcmp(replaced, old_code, MCOUNT_INSN_SIZE) != 0)
- return 2;
+ return -EINVAL;
- ret = __copy_to_user_inatomic((char __user *)ip, new_code,
- MCOUNT_INSN_SIZE);
- WARN_ON_ONCE(ret);
+ if (__copy_to_user_inatomic((char __user *)ip, new_code,
+ MCOUNT_INSN_SIZE))
+ return -EPERM;
sync_core();