linux-kernel - Re: [PATCH] s390/vfio-ap: Fix module unload memory leak of matrix

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Date:   Fri, 18 Jun 2021 11:10:18 -0300
From:   Jason Gunthorpe <jgg@...dia.com>
To:     "Jason J. Herne" <jjherne@...ux.ibm.com>
Cc:     linux-s390@...r.kernel.org, linux-kernel@...r.kernel.org,
        pasic@...ux.ibm.com, akrowiak@...ux.ibm.com
Subject: Re: [PATCH] s390/vfio-ap: Fix module unload memory leak of matrix_dev

On Fri, Jun 18, 2021 at 09:35:24AM -0400, Jason J. Herne wrote:
> vfio_ap_matrix_dev_release is shadowing the global matrix_dev with driver
> data that never gets set. So when release is called we end up not freeing
> matrix_dev. The fix is to remove the shadow variable and just free the
> global.

I would clarify this commit message to say that the drv_data of the
matrix_dev is never set and so dev_get_drvdata() always returns NULL

And I would suggest to use 

  container_of(dev, struct ap_matrix_dev, dev)

instead of the global variable, and probably NULL the global
too..

Jason