[tip: core/kprobes] x86/ftrace: Mark ftrace_modify_code_direct() __ref

[tip-bot2 for Borislav Petkov]

The following commit has been merged into the core/kprobes branch of tip:

Commit-ID:     38ebd8d119245eecb99fe00b0f57e269baf22767
Gitweb:        https://git.kernel.org/tip/38ebd8d119245eecb99fe00b0f57e269baf22767
Author:        Borislav Petkov <bp@xxxxxxx>
AuthorDate:    Mon, 18 Nov 2019 18:20:12 +01:00
Committer:     Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Wed, 27 Nov 2019 07:44:24 +01:00

x86/ftrace: Mark ftrace_modify_code_direct() __ref

... because it calls the .init.text function text_poke_early(). That is
ok because it does call that function early, during boot.

Fixes: 9706f7c3531f ("x86/ftrace: Use text_poke()")
Suggested-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Acked-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Daniel Bristot de Oliveira <bristot@xxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: https://lkml.kernel.org/r/20191116204607.GC23231@xxxxxxx
---
 arch/x86/kernel/ftrace.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 2a179fb..108ee96 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -99,7 +99,12 @@ static int ftrace_verify_code(unsigned long ip, const char *old_code)
 	return 0;
 }
 
-static int
+/*
+ * Marked __ref because it calls text_poke_early() which is .init.text. That is
+ * ok because that call will happen early, during boot, when .init sections are
+ * still present.
+ */
+static int __ref
 ftrace_modify_code_direct(unsigned long ip, const char *old_code,
 			  const char *new_code)
 {