linux-kernel - Re: [PATCH 1/3] RISC-V: Fix .init section permission update

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Date:   Tue, 02 Feb 2021 18:34:54 -0800 (PST)
From:   Palmer Dabbelt <palmer@...belt.com>
To:     Atish Patra <Atish.Patra@....com>
CC:     linux-kernel@...r.kernel.org, Atish Patra <Atish.Patra@....com>,
        geert@...ux-m68k.org, aou@...s.berkeley.edu,
        Anup Patel <Anup.Patel@....com>, ardb@...nel.org,
        kirill.shutemov@...ux.intel.com, linux-riscv@...ts.infradead.org,
        ndesaulniers@...ogle.com, Paul Walmsley <paul.walmsley@...ive.com>,
        svancau@...il.com, zong.li@...ive.com
Subject:     Re: [PATCH 1/3] RISC-V: Fix .init section permission update

On Fri, 29 Jan 2021 11:00:36 PST (-0800), Atish Patra wrote:
> .init section permission should only updated to non-execute if
> STRICT_KERNEL_RWX is enabled. Otherwise, this will lead to a kernel hang.
>
> Fixes: 19a00869028f ("RISC-V: Protect all kernel sections including init early")
>
> Suggested-by: Geert Uytterhoeven <geert@...ux-m68k.org>
> Reported-by: Geert Uytterhoeven <geert@...ux-m68k.org>
> Signed-off-by: Atish Patra <atish.patra@....com>
> ---
>  arch/riscv/kernel/setup.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
> index 3fa3f26dde85..c7c0655dd45b 100644
> --- a/arch/riscv/kernel/setup.c
> +++ b/arch/riscv/kernel/setup.c
> @@ -293,6 +293,8 @@ void free_initmem(void)
>  	unsigned long init_begin = (unsigned long)__init_begin;
>  	unsigned long init_end = (unsigned long)__init_end;
>
> -	set_memory_rw_nx(init_begin, (init_end - init_begin) >> PAGE_SHIFT);
> +	if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX))
> +		set_memory_rw_nx(init_begin, (init_end - init_begin) >> PAGE_SHIFT);
> +
>  	free_initmem_default(POISON_FREE_INITMEM);
>  }

Thanks, this is on fixes.