From: David Ahern <dsahern@gmail.com>
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
Subject: Re: [PATCH] net: Change the layout of structure trace_event_raw_fib_table_lookup
Date: Mon, 13 Aug 2018 08:40:32 -0600 [thread overview]
Message-ID: <e9697bf5-11eb-68ec-238f-aedb724c8c17@gmail.com> (raw)
In-Reply-To: <1534127212-13186-1-git-send-email-zong@andestech.com>
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?
next prev parent reply other threads:[~2018-08-13 14:40 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-13 2:26 [PATCH] net: Change the layout of structure trace_event_raw_fib_table_lookup Zong Li
2018-08-13 14:40 ` David Ahern [this message]
2018-08-14 1:13 ` Zong Li
2018-08-13 16:37 ` David Miller
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