diff --git a/Makefile b/Makefile
index 130926fa592e..c2344755a1bb 100644
--- a/Makefile
+++ b/Makefile
@@ -1118,7 +1118,8 @@ endif
 ifdef CONFIG_RUST
 	# Always pass -Zsanitizer-cfi-normalize-integers as CONFIG_RUST selects
 	# CONFIG_CFI_ICALL_NORMALIZE_INTEGERS.
-	RUSTC_FLAGS_CFI   := -Zsanitizer=kcfi -Zsanitizer-cfi-normalize-integers
+	# Disable function merging as LLVM incorrectly merges functions with different KCFI types.
+	RUSTC_FLAGS_CFI   := -Zsanitizer=kcfi -Zsanitizer-cfi-normalize-integers -Zmerge-functions=disabled
 	KBUILD_RUSTFLAGS += $(RUSTC_FLAGS_CFI)
 	export RUSTC_FLAGS_CFI
 endif