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

From: Steven Rostedt
Date: Wed Aug 26 2015 - 16:30:26 EST


On Wed, 26 Aug 2015 06:32:55 -0400
Jeff Layton <jlayton@xxxxxxxxxxxxxxx> wrote:


> > 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

Ug, I hate that printk option. It can be dangerous.

> want to pass a NULL pointer to it. We do want to save a copy of the
> sockaddr.

Save just enough for what you need to print out. Don't waste any space
on the ring buffer that isn't necessary.

-- Steve

>
> > __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,
>
>

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/