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Subject: Re: [Patch v2] media: ti-vpe: cal: fix a kernel oops when unloading
 module
To:     Benoit Parrot <bparrot@ti.com>, Hans Verkuil <hverkuil@xs4all.nl>
CC:     <linux-media@vger.kernel.org>, <devicetree@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <stable@vger.kernel.org>
References: <20200306130839.1209-1-bparrot@ti.com>
From:   Tomi Valkeinen <tomi.valkeinen@ti.com>
Message-ID: <326ff891-baae-47cb-849d-4cd07793236c@ti.com>
Date:   Tue, 10 Mar 2020 10:56:08 +0200
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On 06/03/2020 15:08, Benoit Parrot wrote:
> After the switch to use v4l2_async_notifier_add_subdev() and
> v4l2_async_notifier_cleanup(), unloading the ti_cal module would casue a
> kernel oops.
> 
> This was root cause to the fact that v4l2_async_notifier_cleanup() tries
> to kfree the asd pointer passed into v4l2_async_notifier_add_subdev().
> 
> In our case the asd reference was from a statically allocated struct.
> So in effect v4l2_async_notifier_cleanup() was trying to free a pointer
> that was not kalloc.
> 
> So here we switch to using a kzalloc struct instead of a static one.
> To acheive this we re-order some of the calls to prevent asd allocation
> from leaking.
> 
> Fixes: d079f94c9046 ("media: platform: Switch to v4l2_async_notifier_add_subdev")
> 
> Cc: stable@vger.kernel.org
> Signed-off-by: Benoit Parrot <bparrot@ti.com>
> ---
> Changes since v1:
> - fix asd allocation leak
> 
>   drivers/media/platform/ti-vpe/cal.c | 13 ++++++++-----
>   1 file changed, 8 insertions(+), 5 deletions(-)

Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

  Tomi

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