5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Samuel Holland <samuel.holland@xxxxxxxxxx> commit 6f9dc684cae638dda0570154509884ee78d0f75c upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/Kconfig | 1 + 1 file changed, 1 insertion(+) --- a/arch/Kconfig +++ b/arch/Kconfig @@ -605,6 +605,7 @@ config SHADOW_CALL_STACK bool "Clang Shadow Call Stack" depends on CC_IS_CLANG && ARCH_SUPPORTS_SHADOW_CALL_STACK depends on DYNAMIC_FTRACE_WITH_REGS || !FUNCTION_GRAPH_TRACER + depends on MMU help This option enables Clang's Shadow Call Stack, which uses a shadow stack to protect function return addresses from being
