[PATCH 5.10 446/545] ftrace/x86: Add back ftrace_expected assignment

[Greg Kroah-Hartman]

From: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>

commit ac6c1b2ca77e722a1e5d651f12f437f2f237e658 upstream.

When a ftrace_bug happens (where ftrace fails to modify a location) it is
helpful to have what was at that location as well as what was expected to
be there.

But with the conversion to text_poke() the variable that assigns the
expected for debugging was dropped. Unfortunately, I noticed this when I
needed it. Add it back.

Link: https://lkml.kernel.org/r/20220726101851.069d2e70@xxxxxxxxxxxxxxxxxx

Cc: "x86@xxxxxxxxxx" <x86@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Fixes: 768ae4406a5c ("x86/ftrace: Use text_poke()")
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 arch/x86/kernel/ftrace.c |    1 +
 1 file changed, 1 insertion(+)

--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -93,6 +93,7 @@ static int ftrace_verify_code(unsigned l
 
 	/* Make sure it is what we expect it to be */
 	if (memcmp(cur_code, old_code, MCOUNT_INSN_SIZE) != 0) {
+		ftrace_expected = old_code;
 		WARN_ON(1);
 		return -EINVAL;
 	}