Re: [PATCH v2] sound: core: fix device ownership model in card and pcm

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Wed, Aug 02, 2023 at 10:43:49AM -0700, cujomalainey@chromium.org wrote:
> From: Curtis Malainey <cujomalainey@chromium.org>
> 
> The current implementation of how devices are released is valid for
> production use cases (root control of memory is handled by card_dev, all
> other devices are no-ops).
> 
> This model does not work though in a kernel hacking environment where
> KASAN and delayed release on kobj is enabled. If the card_dev device is
> released before any of the child objects a use-after-free bug is caught
> by KASAN as the delayed release still has a reference to the devices
> that were freed by the card_dev release. Also both snd_card and snd_pcm
> both own two devices internally, so even if they released independently,
> the shared struct would result in another use after free.
> 
> Solution is to move the child devices into their own memory so they can
> be handled independently and released on their own schedule.
> 
> Signed-off-by: Curtis Malainey <cujomalainey@chromium.org>
> Cc: Doug Anderson <dianders@chromium.org>
> ---
>  include/sound/core.h            |  2 +-
>  include/sound/pcm.h             |  2 +-
>  sound/aoa/soundbus/i2sbus/pcm.c |  4 ++--
>  sound/core/control.c            | 21 +++++++++++++++------
>  sound/core/control_led.c        |  4 ++--
>  sound/core/pcm.c                | 30 ++++++++++++++++++++----------
>  sound/usb/media.c               |  4 ++--
>  7 files changed, 43 insertions(+), 24 deletions(-)
> 

Hi,

This is the friendly patch-bot of Greg Kroah-Hartman.  You have sent him
a patch that has triggered this response.  He used to manually respond
to these common problems, but in order to save his sanity (he kept
writing the same thing over and over, yet to different people), I was
created.  Hopefully you will not take offence and will fix the problem
in your patch and resubmit it so that it can be accepted into the Linux
kernel tree.

You are receiving this message because of the following common error(s)
as indicated below:

- This looks like a new version of a previously submitted patch, but you
  did not list below the --- line any changes from the previous version.
  Please read the section entitled "The canonical patch format" in the
  kernel file, Documentation/process/submitting-patches.rst for what
  needs to be done here to properly describe this.


If you wish to discuss this problem further, or you have questions about
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