[DTrace-devel] [PATCH] Eliminate no-longer-needed DT_CG_ALLOCA_NULLPTR workaround

[Kris Van Hees]

On Tue, Apr 26, 2022 at 01:07:00PM -0400, eugene.loh--- via DTrace-devel wrote:
> From: Eugene Loh <eugene.loh at oracle.com>
> 
> Signed-off-by: Eugene Loh <eugene.loh at oracle.com>

Oh, hm, I missed that.  Woops, yes , tha tis no longer needed at all.

Reviewed-by: Kris Van Hees <kris.van.hees at oracle.com>

... and I will add it to dev since I am preparing the next errata release
right now.

> ---
>  bpf/inet_ntoa.S | 20 --------------------
>  1 file changed, 20 deletions(-)
> 
> diff --git a/bpf/inet_ntoa.S b/bpf/inet_ntoa.S
> index f8a3f112..ff36e226 100644
> --- a/bpf/inet_ntoa.S
> +++ b/bpf/inet_ntoa.S
> @@ -155,26 +155,6 @@ dt_inet_ntoa:
>  	mov	SRC, %r1
>  	mov	DST, %r2
>  
> -#if 1
> -#define BPF_FUNC_probe_read	4
> -	/*
> -	 * FIXME: copy src data over
> -	 *
> -	 * Currently, the code generator's handling of DT_CG_ALLOCA_NULLPTR
> -	 * is such that there are scenarios where the BPF verifier thinks an
> -	 * unsuitable value is being passed in as the "src" argument.  Until
> -	 * this is fixed, simply use bpf_probe_read() to copy the src data
> -	 * onto the BPF stack.  Reset the src argument to point to that
> -	 * stack location.
> -	 */
> -	mov	%r3, %r1
> -	mov	%r2, 4
> -	mov	SRC, %fp
> -	add	SRC, -4
> -	mov	%r1, SRC
> -	call	BPF_FUNC_probe_read
> -#endif
> -
>  	mov	%r3, 0
>  	lddw	LEN, STRSZ
>  
> -- 
> 2.18.4
> 
> 
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