From 4473c3cc6b464c1430f79eb9f8137e1a066e1699 Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz@infradead.org>
Date: Fri, 16 Sep 2022 18:49:27 +0800
Subject: [PATCH] um: Add missing apply_returns()

stable inclusion
from stable-v5.10.133
commit 8e2774270aa319f552fab969bc4500e412d2566b
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5PTAS
CVE: CVE-2022-29900,CVE-2022-23816,CVE-2022-29901

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=8e2774270aa319f552fab969bc4500e412d2566b

--------------------------------

commit 564d998106397394b6aad260f219b882b3347e62 upstream.

Implement apply_returns() stub for UM, just like all the other patching
routines.

Fixes: 15e67227c49a ("x86: Undo return-thunk damage")
Reported-by: Randy Dunlap <rdunlap@infradead.org)
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/Ys%2Ft45l%2FgarIrD0u@worktop.programming.kicks-ass.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Lin Yujun <linyujun809@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
---
 arch/um/kernel/um_arch.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c
index 2676ac322146..26af24b5d900 100644
--- a/arch/um/kernel/um_arch.c
+++ b/arch/um/kernel/um_arch.c
@@ -362,6 +362,10 @@ void apply_retpolines(s32 *start, s32 *end)
 {
 }
 
+void apply_returns(s32 *start, s32 *end)
+{
+}
+
 void apply_alternatives(struct alt_instr *start, struct alt_instr *end)
 {
 }
-- 
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