When using the shadow call stack sanitizer, all code must be compiled with the -ffixed-x18 flag, but this flag is not currently being passed to Rust. This results in crashes that are extremely difficult to debug.
To ensure that nobody else has to go through the same debugging session that I had to, prevent configurations that enable both SHADOW_CALL_STACK and RUST.
It is rather common for people to backport 724a75ac9542 ("arm64: rust: Enable Rust support for AArch64"), so I recommend applying this fix all the way back to 6.1.
Cc: stable@vger.kernel.org # 6.1 and later Fixes: 724a75ac9542 ("arm64: rust: Enable Rust support for AArch64") Signed-off-by: Alice Ryhl aliceryhl@google.com --- arch/Kconfig | 1 + 1 file changed, 1 insertion(+)
diff --git a/arch/Kconfig b/arch/Kconfig index 975dd22a2dbd..238448a9cb71 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -690,6 +690,7 @@ 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 !RUST depends on MMU help This option enables the compiler's Shadow Call Stack, which