[PATCH] x86/ibt: make is_endbr() notrace

[Menglong Dong]

is_endbr() is called in __ftrace_return_to_handler -> fprobe_return ->
kprobe_multi_link_exit_handler -> is_endbr.

It is not protected by the "bpf_prog_active", so it can't be traced by
kprobe-multi, which can cause recurring and panic the kernel. Fix it by
make it notrace.

Fixes: 72e213a7ccf9 ("x86/ibt: Clean up is_endbr()")
Signed-off-by: Menglong Dong <dongml2@xxxxxxxxxxxxxxx>
---
 arch/x86/kernel/alternative.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 69fb818df2ee..f67a31c77c89 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -1108,7 +1108,7 @@ void __init_or_module noinline apply_returns(s32 *start, s32 *end) { }
 
 #ifdef CONFIG_X86_KERNEL_IBT
 
-__noendbr bool is_endbr(u32 *val)
+__noendbr notrace bool is_endbr(u32 *val)
 {
 	u32 endbr;
 
-- 
2.51.0