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To:     Hongyu Xie <xy521521@gmail.com>, gregkh@linuxfoundation.org,
        mathias.nyman@intel.com
Cc:     linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
        Hongyu Xie <xiehongyu1@kylinos.cn>, stable@vger.kernel.org
References: <20220209025234.25230-1-xy521521@gmail.com>
From:   Mathias Nyman <mathias.nyman@linux.intel.com>
Subject: Re: [PATCH -next v2] xhci: fix two places when dealing with return
 value of function xhci_check_args
Message-ID: <89d59749-8ca3-b30b-4da6-a6e567528d1b@linux.intel.com>
Date:   Wed, 9 Feb 2022 11:29:22 +0200
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On 9.2.2022 4.52, Hongyu Xie wrote:
> From: Hongyu Xie <xiehongyu1@kylinos.cn>
> 
> xhci_check_args returns 4 types of value, -ENODEV, -EINVAL, 1 and 0.
> xhci_urb_enqueue and xhci_check_streams_endpoint return -EINVAL if
> the return value of xhci_check_args <= 0.
> This will cause a problem.
> For example, r8152_submit_rx calling usb_submit_urb in
> drivers/net/usb/r8152.c.
> r8152_submit_rx will never get -ENODEV after submiting an urb
> when xHC is halted,
> because xhci_urb_enqueue returns -EINVAL in the very beginning.
> 
> Fixes: 203a86613fb3 ("xhci: Avoid NULL pointer deref when host dies.")
> Cc: stable@vger.kernel.org
> Signed-off-by: Hongyu Xie <xiehongyu1@kylinos.cn>
> ---

Thanks, added to queue.
Changed the commit message and header a bit:

"xhci: Prevent futile URB re-submissions due to incorrect return value.
    
The -ENODEV return value from xhci_check_args() is incorrectly changed
to -EINVAL in a couple places before propagated further.
    
xhci_check_args() returns 4 types of value, -ENODEV, -EINVAL, 1 and 0.
xhci_urb_enqueue and xhci_check_streams_endpoint return -EINVAL if
the return value of xhci_check_args <= 0.
This causes problems for example r8152_submit_rx, calling usb_submit_urb
in drivers/net/usb/r8152.c.
r8152_submit_rx will never get -ENODEV after submiting an urb when xHC
is halted because xhci_urb_enqueue returns -EINVAL in the very beginning."

Let me know if you disagree with this.

Thanks
-Mathias