[DTrace-devel] [PATCH] Get execargs from user space

[Kris Van Hees]

On Wed, Mar 19, 2025 at 02:32:30AM -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>

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

I expect this is a failure on arm64 only?  That would make sense since it is
the only arch we currently work with for DTrace that has kernels where the
specific probe_read_kernel/user separation is enforced. 

I'll fix the comment as indicated below while merging.

> ---
>  bpf/bvar_execargs.S | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/bpf/bvar_execargs.S b/bpf/bvar_execargs.S
> index 1c47cafb2..08844f15f 100644
> --- a/bpf/bvar_execargs.S
> +++ b/bpf/bvar_execargs.S
> @@ -65,7 +65,7 @@ dt_bvar_execargs:
>  	mov	%r1, %r9
>  	mov	%r2, %r8
>  	mov	%r3, %r7
> -	call	BPF_FUNC_probe_read		/* bpf_probe_read(&args, len + 1, arg_start) */
> +	call	BPF_FUNC_probe_read_user	/* bpf_probe_read(&args, len + 1, arg_start) */

comment should also mention bpf_probe_read_user

>  	jne	%r0, 0, .Lerror
>  
>  	/* loop over args and replace '\0' with ' ' */
> -- 
> 2.43.5
> 
> 
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