[PATCH] scs: add CONFIG_MMU dependency for vfree_atomic()

From: Samuel Holland
Date: Mon Jan 22 2024 - 14:05:51 EST


The shadow call stack implementation fails to build without CONFIG_MMU:

ld.lld: error: undefined symbol: vfree_atomic
>>> referenced by scs.c
>>> kernel/scs.o:(scs_free) in archive vmlinux.a

Fixes: a2abe7cbd8fe ("scs: switch to vmapped shadow stacks")
Signed-off-by: Samuel Holland <samuel.holland@xxxxxxxxxx>
---

arch/Kconfig | 1 +
1 file changed, 1 insertion(+)

diff --git a/arch/Kconfig b/arch/Kconfig
index c91917b50873..a5af0edd3eb8 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -673,6 +673,7 @@ config SHADOW_CALL_STACK
bool "Shadow Call Stack"
depends on ARCH_SUPPORTS_SHADOW_CALL_STACK
depends on DYNAMIC_FTRACE_WITH_ARGS || DYNAMIC_FTRACE_WITH_REGS || !FUNCTION_GRAPH_TRACER
+ depends on MMU
help
This option enables the compiler's Shadow Call Stack, which
uses a shadow stack to protect function return addresses from
--
2.43.0