From 6268a0704b97e65d2753de9bbc7c8a43ef383494 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Google)" Date: Fri, 9 Dec 2022 10:52:47 -0500 Subject: [PATCH] ftrace/x86: Add back ftrace_expected for ftrace bug reports commit fd3dc56253acbe9c641a66d312d8393cd55eb04c upstream. After someone reported a bug report with a failed modification due to the expected value not matching what was found, it came to my attention that the ftrace_expected is no longer set when that happens. This makes for debugging the issue a bit more difficult. Set ftrace_expected to the expected code before calling ftrace_bug, so that it shows what was expected and why it failed. Link: https://lore.kernel.org/all/CA+wXwBQ-VhK+hpBtYtyZP-NiX4g8fqRRWithFOHQW-0coQ3vLg@mail.gmail.com/ Link: https://lore.kernel.org/linux-trace-kernel/20221209105247.01d4e51d@gandalf.local.home Cc: Masami Hiramatsu Cc: Andrew Morton Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: "x86@kernel.org" Cc: Borislav Petkov Cc: Ingo Molnar Cc: stable@vger.kernel.org Fixes: 768ae4406a5c ("x86/ftrace: Use text_poke()") Signed-off-by: Steven Rostedt (Google) Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/ftrace.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c index b3c9ef0..4017da3 100644 --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -219,7 +219,9 @@ void ftrace_replace_code(int enable) ret = ftrace_verify_code(rec->ip, old); if (ret) { + ftrace_expected = old; ftrace_bug(ret, rec); + ftrace_expected = NULL; return; } } -- 2.7.4