6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Zongmin Zhou commit 298510bbc7c3017c0faf481c6ea66f1065b657b4 upstream. errata_probe_ghostwrite() only marks the CPU as vulnerable when it is called at the RISCV_ALTERNATIVES_EARLY_BOOT stage, and the mitigation in ghostwrite_enable_mitigation() only takes effect if the vulnerable state was recorded before the boot alternatives are patched. The early boot stage is only executed when CONFIG_RISCV_ALTERNATIVE_EARLY is enabled, which currently is only selected by ERRATA_THEAD_MAE. In a kernel built with ERRATA_THEAD_GHOSTWRITE=y but ERRATA_THEAD_MAE=n, the early alternatives never run, so ghostwrite_state is never set to VULNERABLE: ghostwrite_enable_mitigation() returns false, xtheadvector remains enabled, and sysfs reports "Not affected" on a vulnerable T-Head C9xx CPU. Select RISCV_ALTERNATIVE_EARLY from ERRATA_THEAD_GHOSTWRITE so that the vulnerability is detected in the early boot stage and the default mitigation is applied. Fixes: 4bf97069239b ("riscv: Add ghostwrite vulnerability") Signed-off-by: Zongmin Zhou Link: https://patch.msgid.link/20260917074843.52716-1-min_halo@163.com Cc: stable@vger.kernel.org Signed-off-by: Paul Walmsley Signed-off-by: Greg Kroah-Hartman --- arch/riscv/Kconfig.errata | 1 + 1 file changed, 1 insertion(+) --- a/arch/riscv/Kconfig.errata +++ b/arch/riscv/Kconfig.errata @@ -145,6 +145,7 @@ config ERRATA_THEAD_PMU config ERRATA_THEAD_GHOSTWRITE bool "Apply T-Head Ghostwrite errata" depends on ERRATA_THEAD && RISCV_ISA_XTHEADVECTOR + select RISCV_ALTERNATIVE_EARLY default y help The T-Head C9xx cores have a vulnerability in the xtheadvector