Re: [PATCH master] ARM64: setupc: don't invoke KASAN before relocation

[Sascha Hauer <sha@pengutronix.de>]

On Sat, Apr 15, 2023 at 10:34:47AM +0200, Ahmad Fatoum wrote:
> Plain memset and memcpy are checked by KASAN if enabled before calling
> unchecked __memset and __memcpy respectively.
> 
> KASAN uses a kasan_initialized variable as first condition in its memory
> check, but that only works after relocation. For that reason, we must
> take care not to invoke KASAN before then. This was done for ARM32, but
> was missing for ARM64. Do so now.
> 
> This fixes an annoying issue where network booting a KASAN-enabled barebox
> twice in a row would fail: The first happened to work because the memory
> kasan_initialized was placed at was zero. The second would behave
> erratically, because BSS initialization would silently fail and barebox
> static storage would then be initialized with the final values of the
> previous run.
> 
> Fixes: 932ef7a02e2f ("ARM: Add KASan support")
> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>

Applied, thanks

Sascha

> ---
> I wondered if there's a way to print a KASAN error that early, but it's
> not easy. Calling even global_variable_offset() in kasan_report caused
> infinite recursion, despite use of __no_sanitize_address. Printing
> unconditionally could be a way around this.
> ---
>  arch/arm/cpu/setupc_64.S | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm/cpu/setupc_64.S b/arch/arm/cpu/setupc_64.S
> index d64281c148fc..f38f893be90b 100644
> --- a/arch/arm/cpu/setupc_64.S
> +++ b/arch/arm/cpu/setupc_64.S
> @@ -14,7 +14,7 @@ ENTRY(setup_c)
>  	mov	x1, #0
>  	ldr	x2, =__bss_stop
>  	sub	x2, x2, x0
> -	bl	memset			/* clear bss */
> +	bl	__memset		/* clear bss */
>  	mov	x30, x15
>  	ret
>  ENDPROC(setup_c)
> @@ -63,7 +63,7 @@ ENTRY(relocate_to_adr)
>  	sub	x19, x19, x1		/* sub address where we are actually running */
>  	add	x19, x19, x0		/* add address where we are going to run */
>  
> -	bl	memcpy			/* copy binary */
> +	bl	__memcpy		/* copy binary */
>  
>  	bl	sync_caches_for_execution
>  
> -- 
> 2.39.2
> 
> 
> 

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