Re: [PATCH net] qmi_wwan: Clone the skb when in pass-through mode

From: Kristian Evensen <kristian.evensen@gmail.com>
To: "Bjørn Mork" <bjorn@mork.no>
Cc: Network Development <netdev@vger.kernel.org>, subashab@codeaurora.org
Subject: Re: [PATCH net] qmi_wwan: Clone the skb when in pass-through mode
Date: Mon, 14 Jun 2021 19:02:15 +0200	[thread overview]
Message-ID: <CAKfDRXi=4Vsf_a40EdLsyunjKGXaFnA0ZeNbMcBDw1Tk+eSzMQ@mail.gmail.com> (raw)
In-Reply-To: <CAKfDRXgZeWCeGXhfukeeAGrHHUMtsHWRPEebUkZf07QCnU4CFw@mail.gmail.com>

Hi Bjørn,

On Mon, Jun 14, 2021 at 5:49 PM Kristian Evensen
<kristian.evensen@gmail.com> wrote:
> I will do some more testing tomorrow and see if I can figure out
> something. So far, the only thing I know is that if I try to perform a
> more demanding transfer (like downloading a file) using qmi_wwan +
> rmnet then I get a kernel oops immediatly.

I got curios and decided to test your proposed changed today.
Replacing the call to netif_rx() with return 1, and then letting
usbnet_skb_return() do the netif_rx() call, seems to have resolved the
issue. At least I am not longer able to trigger the oops using my
earlier reproducer (running a couple of Speedtest).

Unless someone beats me to it, I will prepare another patch tomorrow.
Thanks for the help.

Kristian