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From: Yasushi SHOJI <yashi@spacecubics.com>
To: Hangyu Hua <hbh25y@gmail.com>
Cc: Wolfgang Grandegger <wg@grandegger.com>,
	Marc Kleine-Budde <mkl@pengutronix.de>,
	David Miller <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Vincent Mailhol <mailhol.vincent@wanadoo.fr>,
	stefan.maetje@esd.eu, Pavel Skripkin <paskripkin@gmail.com>,
	remigiusz.kollataj@mobica.com,
	linux-can <linux-can@vger.kernel.org>,
	netdev <netdev@vger.kernel.org>,
	open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] can: mcba_usb: fix possible double dev_kfree_skb in mcba_usb_start_xmit
Date: Wed, 23 Mar 2022 08:08:16 +0900	[thread overview]
Message-ID: <CAGLTpnK=4Gd8S488osvrbttkMvtsPy8eCGspV4-=z2N3UGZ5rw@mail.gmail.com> (raw)
In-Reply-To: <20220311080208.45047-1-hbh25y@gmail.com>

Hi Hangyu,

On Fri, Mar 11, 2022 at 5:02 PM Hangyu Hua <hbh25y@gmail.com> wrote:
>
> There is no need to call dev_kfree_skb when usb_submit_urb fails beacause
> can_put_echo_skb deletes original skb and can_free_echo_skb deletes the cloned
> skb.

So, it's more like, "we don't need to call dev_kfree_skb() after
can_put_echo_skb()
because can_put_echo_skb() consumes the given skb.".  It seems it doesn't depend
on the condition of usb_submit_urb().  Plus, we don't see the "cloned
skb" at the
call site.

Would you mind adding a comment on can_put_echo_skb(), in a separate patch,
saying the fact that it consumes the skb?

ems_usb.c, gs_usb.c and possibly some others seem to call
dev_kfree_skb() as well.
Are they affected?

Best,
-- 
           yashi

  parent reply	other threads:[~2022-03-22 23:08 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-11  8:02 [PATCH] can: mcba_usb: fix possible double dev_kfree_skb in mcba_usb_start_xmit Hangyu Hua
2022-03-21  1:47 ` Hangyu Hua
2022-03-22 23:08 ` Yasushi SHOJI [this message]
2022-03-23  2:12   ` Hangyu Hua

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