The quilt patch titled Subject: scs: add CONFIG_MMU dependency for vfree_atomic() has been removed from the -mm tree. Its filename was scs-add-config_mmu-dependency-for-vfree_atomic.patch This patch was dropped because it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Samuel Holland <samuel.holland@xxxxxxxxxx> Subject: scs: add CONFIG_MMU dependency for vfree_atomic() Date: Mon, 22 Jan 2024 09:52:01 -0800 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 Link: https://lkml.kernel.org/r/20240122175204.2371009-1-samuel.holland@xxxxxxxxxx Fixes: a2abe7cbd8fe ("scs: switch to vmapped shadow stacks") Signed-off-by: Samuel Holland <samuel.holland@xxxxxxxxxx> Reviewed-by: Sami Tolvanen <samitolvanen@xxxxxxxxxx> Cc: Will Deacon <will@xxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/Kconfig | 1 + 1 file changed, 1 insertion(+) --- a/arch/Kconfig~scs-add-config_mmu-dependency-for-vfree_atomic +++ a/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 _ Patches currently in -mm which might be from samuel.holland@xxxxxxxxxx are