linux-kernel - Re: [PATCH] [media] hdpvr: Fix an error handling path in hdpvr

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Message-ID: <CAAeHK+xNvsUbwWWF-Nw9pmx8B3ngwWpN9Pq5H3ZOu3t2_GaKOQ@mail.gmail.com>
Date:   Fri, 22 Sep 2017 15:16:24 +0200
From:   Andrey Konovalov <andreyknvl@...gle.com>
To:     Arvind Yadav <arvind.yadav.cs@...il.com>
Cc:     Hans Verkuil <hverkuil@...all.nl>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        Kostya Serebryany <kcc@...gle.com>,
        syzkaller <syzkaller@...glegroups.com>,
        linux-media@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] [media] hdpvr: Fix an error handling path in hdpvr_probe()

On Fri, Sep 22, 2017 at 3:07 PM, Arvind Yadav <arvind.yadav.cs@...il.com> wrote:
> Here, hdpvr_register_videodev() is responsible for setup and
> register a video device. Also defining and initializing a worker.
> hdpvr_register_videodev() is calling by hdpvr_probe at last.
> So No need to flash any work here.
> Unregister v4l2, free buffers and memory. If hdpvr_probe() will fail.
>
> Signed-off-by: Arvind Yadav <arvind.yadav.cs@...il.com>

Reported-by: Andrey Konovalov <andreyknvl@...gle.com>

Thanks, this fixes the crash!

Tested-by: Andrey Konovalov <andreyknvl@...gle.com>

> ---
>  drivers/media/usb/hdpvr/hdpvr-core.c | 26 +++++++++++++++-----------
>  1 file changed, 15 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/media/usb/hdpvr/hdpvr-core.c b/drivers/media/usb/hdpvr/hdpvr-core.c
> index dbe29c6..1e8cbaf 100644
> --- a/drivers/media/usb/hdpvr/hdpvr-core.c
> +++ b/drivers/media/usb/hdpvr/hdpvr-core.c
> @@ -292,7 +292,7 @@ static int hdpvr_probe(struct usb_interface *interface,
>         /* register v4l2_device early so it can be used for printks */
>         if (v4l2_device_register(&interface->dev, &dev->v4l2_dev)) {
>                 dev_err(&interface->dev, "v4l2_device_register failed\n");
> -               goto error;
> +               goto error_free_dev;
>         }
>
>         mutex_init(&dev->io_mutex);
> @@ -301,7 +301,7 @@ static int hdpvr_probe(struct usb_interface *interface,
>         dev->usbc_buf = kmalloc(64, GFP_KERNEL);
>         if (!dev->usbc_buf) {
>                 v4l2_err(&dev->v4l2_dev, "Out of memory\n");
> -               goto error;
> +               goto error_v4l2_unregister;
>         }
>
>         init_waitqueue_head(&dev->wait_buffer);
> @@ -339,13 +339,13 @@ static int hdpvr_probe(struct usb_interface *interface,
>         }
>         if (!dev->bulk_in_endpointAddr) {
>                 v4l2_err(&dev->v4l2_dev, "Could not find bulk-in endpoint\n");
> -               goto error;
> +               goto error_put_usb;
>         }
>
>         /* init the device */
>         if (hdpvr_device_init(dev)) {
>                 v4l2_err(&dev->v4l2_dev, "device init failed\n");
> -               goto error;
> +               goto error_put_usb;
>         }
>
>         mutex_lock(&dev->io_mutex);
> @@ -353,7 +353,7 @@ static int hdpvr_probe(struct usb_interface *interface,
>                 mutex_unlock(&dev->io_mutex);
>                 v4l2_err(&dev->v4l2_dev,
>                          "allocating transfer buffers failed\n");
> -               goto error;
> +               goto error_put_usb;
>         }
>         mutex_unlock(&dev->io_mutex);
>
> @@ -361,7 +361,7 @@ static int hdpvr_probe(struct usb_interface *interface,
>         retval = hdpvr_register_i2c_adapter(dev);
>         if (retval < 0) {
>                 v4l2_err(&dev->v4l2_dev, "i2c adapter register failed\n");
> -               goto error;
> +               goto error_free_buffers;
>         }
>
>         client = hdpvr_register_ir_rx_i2c(dev);
> @@ -394,13 +394,17 @@ static int hdpvr_probe(struct usb_interface *interface,
>  reg_fail:
>  #if IS_ENABLED(CONFIG_I2C)
>         i2c_del_adapter(&dev->i2c_adapter);
> +error_free_buffers:
>  #endif
> +       hdpvr_free_buffers(dev);
> +error_put_usb:
> +       usb_put_dev(dev->udev);
> +       kfree(dev->usbc_buf);
> +error_v4l2_unregister:
> +       v4l2_device_unregister(&dev->v4l2_dev);
> +error_free_dev:
> +       kfree(dev);
>  error:
> -       if (dev) {
> -               flush_work(&dev->worker);
> -               /* this frees allocated memory */
> -               hdpvr_delete(dev);
> -       }
>         return retval;
>  }
>
> --
> 1.9.1
>