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Subject: Re: [PATCH] net: Change the layout of structure
 trace_event_raw_fib_table_lookup
To:     Zong Li <zong@andestech.com>, rostedt@goodmis.org,
        mingo@redhat.com, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Cc:     zongbox@gmail.com, greentime@andestech.com
References: <1534127212-13186-1-git-send-email-zong@andestech.com>
From:   David Ahern <dsahern@gmail.com>
Message-ID: <e9697bf5-11eb-68ec-238f-aedb724c8c17@gmail.com>
Date:   Mon, 13 Aug 2018 08:40:32 -0600
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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?