Re: [PATCH 2/2] net: sunrpc: fix trace print of &xprt->xpt_remote

[Jeff Layton]

On Tue, 25 Aug 2015 11:34:20 +0530
Pratyush Anand <panand@xxxxxxxxxx> wrote:

> TP_printk() for svc_xprt_dequeue intends to print address of
> xprt->xpt_remote, however it prints address of another structure where
> xprt->xpt_remote has been copied.
> 
> This patch fixes the above behaviour.
> 
> Signed-off-by: Pratyush Anand <panand@xxxxxxxxxx>
> ---
>  include/trace/events/sunrpc.h | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/include/trace/events/sunrpc.h b/include/trace/events/sunrpc.h
> index 937e482d80e9..37b6af1a911a 100644
> --- a/include/trace/events/sunrpc.h
> +++ b/include/trace/events/sunrpc.h
> @@ -556,19 +556,19 @@ TRACE_EVENT(svc_xprt_dequeue,
>  
>  	TP_STRUCT__entry(
>  		__field(struct svc_xprt *, xprt)
> -		__field_struct(struct sockaddr_storage, ss)
> +		__field(struct sockaddr *, addr)
>  		__field(unsigned long, flags)
>  	),
>  
>  	TP_fast_assign(
> -		__entry->xprt = xprt,
> -		xprt ? memcpy(&__entry->ss, &xprt->xpt_remote, sizeof(__entry->ss)) : memset(&__entry->ss, 0, sizeof(__entry->ss));
> +		__entry->xprt = xprt;
> +		__entry->addr =
> +			xprt ? (struct sockaddr *)&xprt->xpt_remote : NULL;

NAK, this is wrong. %pIScp will dereference that address so you don't
want to pass a NULL pointer to it. We do want to save a copy of the
sockaddr.

>  		__entry->flags = xprt ? xprt->xpt_flags : 0;
>  	),
>  
>  	TP_printk("xprt=0x%p addr=%pIScp flags=%s", __entry->xprt,
> -		(struct sockaddr *)&__entry->ss,
> -		show_svc_xprt_flags(__entry->flags))
> +		__entry->addr, show_svc_xprt_flags(__entry->flags))
>  );
>  
>  TRACE_EVENT(svc_wake_up,


-- 
Jeff Layton <jlayton@xxxxxxxxxxxxxxx>
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