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Date:   Wed, 13 Jul 2022 09:34:09 +0300
From:   Ido Schimmel <idosch@idosch.org>
To:     Steven Rostedt <rostedt@goodmis.org>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        Jakub Kicinski <kuba@kernel.org>, Jiri Pirko <jiri@nvidia.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Paolo Abeni <pabeni@redhat.com>, netdev@vger.kernel.org
Subject: Re: [PATCH v2] tracing: devlink: Use static array for string in
 devlink_trap_report even
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References: <20220712185820.002d9fb5@gandalf.local.home>
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On Tue, Jul 12, 2022 at 06:58:20PM -0400, Steven Rostedt wrote:
> From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
> 
> The trace event devlink_trap_report uses the __dynamic_array() macro to
> determine the size of the input_dev_name field. This is because it needs
> to test the dev field for NULL, and will use "NULL" if it is. But it also
> has the size of the dynamic array as a fixed IFNAMSIZ bytes. This defeats
> the purpose of the dynamic array, as this will reserve that amount of
> bytes on the ring buffer, and to make matters worse, it will even save
> that size in the event as the event expects it to be dynamic (for which it
> is not).
> 
> Since IFNAMSIZ is just 16 bytes, just make it a static array and this will
> remove the meta data from the event that records the size.
> 
> Cc: Jakub Kicinski <kuba@kernel.org>
> Cc: Leon Romanovsky <leon@kernel.org>
> Cc: Jiri Pirko <jiri@nvidia.com>
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Eric Dumazet <edumazet@google.com>
> Cc: Paolo Abeni <pabeni@redhat.com>
> Cc: netdev@vger.kernel.org
> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Tested-by: Ido Schimmel <idosch@nvidia.com>