Re: [PATCH] net: Change the layout of structure trace_event_raw_fib_table_lookup

[Zong Li <zongbox@gmail.com>]

David Ahern <dsahern@gmail.com> 於 2018年8月13日 週一 下午10:40寫道：
>
> On 8/12/18 8:26 PM, Zong Li wrote:
> > There is an unalignment access about the structure
> > 'trace_event_raw_fib_table_lookup'.
> >
> > In include/trace/events/fib.h, there is a memory operation which casting
> > the 'src' data member to a pointer, and then store a value to this
> > pointer point to.
> >
> > p32 = (__be32 *) __entry->src;
> > *p32 = flp->saddr;
> >
> > The offset of 'src' in structure trace_event_raw_fib_table_lookup is not
> > four bytes alignment. On some architectures, they don't permit the
> > unalignment access, it need to pay the price to handle this situation in
> > exception handler.
> >
> > Adjust the layout of structure to avoid this case.
> >
> > Signed-off-by: Zong Li <zong@andestech.com>
> > ---
> >  include/trace/events/fib.h | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
>
> Fixes: 9f323973c915 ("net/ipv4: Udate fib_table_lookup tracepoint")
> Acked-by: David Ahern <dsahern@gmail.com>
>
> Do you also need a similar change to fib6_table_lookup in
> include/trace/events/fib6.h?

Hi David,

Though I don't encounter difficulties on it for now, but I think it
has the same situation,
How do you think that also change the layout in include/trace/events/fib6.h?