[PATCH] riscv: Disable STACKPROTECTOR_PER_TASK if GCC_PLUGIN_RANDSTRUCT is enabled

[Palmer Dabbelt]

On Tue, 06 Jul 2021 09:26:21 PDT (-0700), linux at roeck-us.net wrote:
> riscv uses the value of TSK_STACK_CANARY to set
> stack-protector-guard-offset. With GCC_PLUGIN_RANDSTRUCT enabled, that
> value is non-deterministic, and with riscv:allmodconfig often results
> in build errors such as
>
> cc1: error: '8120' is not a valid offset in '-mstack-protector-guard-offset='
>
> Enable STACKPROTECTOR_PER_TASK only if GCC_PLUGIN_RANDSTRUCT is disabled
> to fix the problem.
>
> Fixes: fea2fed201ee5 ("riscv: Enable per-task stack canaries")
> Cc: Guo Ren <guoren at linux.alibaba.com>
> Signed-off-by: Guenter Roeck <linux at roeck-us.net>
> ---
>  arch/riscv/Kconfig | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> index 469a70bd8da6..3afb84fa2190 100644
> --- a/arch/riscv/Kconfig
> +++ b/arch/riscv/Kconfig
> @@ -486,6 +486,7 @@ config CC_HAVE_STACKPROTECTOR_TLS
>
>  config STACKPROTECTOR_PER_TASK
>  	def_bool y
> +	depends on !GCC_PLUGIN_RANDSTRUCT
>  	depends on STACKPROTECTOR && CC_HAVE_STACKPROTECTOR_TLS
>
>  config PHYS_RAM_BASE_FIXED

Thanks, this is on fixes.  I do an allmodconfig build and haven't seen 
these failures, is there something special I need to do to get this 
working?  I know nothing about GCC plugins...