On Wed, Apr 10, 2024 at 11:36:14AM -0400, Steven Rostedt wrote:
> On Mon, 01 Apr 2024 23:48:52 +0000
> Justin Stitt <justinstitt@xxxxxxxxxx> wrote:
>
> > diff --git a/include/trace/events/rpcgss.h b/include/trace/events/rpcgss.h
> > index ba2d96a1bc2f..274c297f1b15 100644
> > --- a/include/trace/events/rpcgss.h
> > +++ b/include/trace/events/rpcgss.h
> > @@ -618,7 +618,7 @@ TRACE_EVENT(rpcgss_context,
> > __entry->timeout = timeout;
> > __entry->window_size = window_size;
> > __entry->len = len;
> > - strncpy(__get_str(acceptor), data, len);
> > + memcpy(__get_str(acceptor), data, len);
> > ),
> >
> > TP_printk("win_size=%u expiry=%lu now=%lu timeout=%u acceptor=%.*s",
>
> WTF, that code is just buggy. Looking at the rpcgss_context event we have:
>
> > TRACE_EVENT(rpcgss_context,
> > TP_PROTO(
> > u32 window_size,
> > unsigned long expiry,
> > unsigned long now,
> > unsigned int timeout,
> > unsigned int len,
> > const u8 *data
> > ),
> >
> > TP_ARGS(window_size, expiry, now, timeout, len, data),
> >
> > TP_STRUCT__entry(
> > __field(unsigned long, expiry)
> > __field(unsigned long, now)
> > __field(unsigned int, timeout)
> > __field(u32, window_size)
> > __field(int, len)
> > __string(acceptor, data)
>
> The __string() macro expects "data" to be a string and does *not* check
> length when copying.
>
> If anything, it needs to be:
>
> __string_len(acceptor, data, len)
>
> as the macro code has changed recently, and the current code will crash!
A general question:
Is there a test suite we should run regularly to build some
confidence in the kernel's observability apparatus? We're building
a menagerie of tests around kdevops, and one area where we know
there is a testing gap is the tracepoints in NFSD and SunRPC.
> > ),
> >
> > TP_fast_assign(
> > __entry->expiry = expiry;
> > __entry->now = now;
> > __entry->timeout = timeout;
> > __entry->window_size = window_size;
> > __entry->len = len;
> > strncpy(__get_str(acceptor), data, len);
>
> Then this needs to be:
>
> __assign_str(acceptor, data);
>
> Note, the length is now saved via __string_len() and not needed here.
>
> I'll go send a patch to fix this.
>
> -- Steve
>
>
> > ),
--
Chuck Lever
