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	Wed, 30 Apr 2014 12:46:48 -0400
From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: Peter Meerwald <pmeerw@pmeerw.net>
Cc: linux-media@vger.kernel.org, sakari.ailus@iki.fi,
	stable@vger.kernel.org
Subject: Re: [PATCH] omap3isp: Fix iommu domain use-after-free in isp_probe() error path
Date: Wed, 30 Apr 2014 18:47:03 +0200
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Hi Peter,

Thank you for the patch.

On Wednesday 30 April 2014 10:13:30 Peter Meerwald wrote:
> isp_save_ctx() is called from omap3isp_put() after iommu_domain_free() in
> the isp_probe() error path
> 
> [    3.205047] Unable to handle kernel NULL pointer dereference at virtual
> address 0000003c [    3.213470] pgd = c0004000
> [    3.216308] [0000003c] *pgd=00000000
> [    3.220031] Internal error: Oops: 5 [#1] PREEMPT ARM
> [    3.225189] Modules linked in:
> [    3.228363] CPU: 0    Not tainted  (3.7.10 #3)
> [    3.232971] PC is at omap2_iommu_save_ctx+0x0/0x34
> [    3.237945] LR is at omap_iommu_save_ctx+0x1c/0x24
> [    3.242919] pc : [<c0026a24>]    lr : [<c02b5878>]    psr: 60000113
> ...
> [    3.425109] [<c0026a24>] (omap2_iommu_save_ctx+0x0/0x34) from
> [<c02b5878>] (omap_iommu_save_ctx+0x1c/0x24)
> [    3.435150] [<c02b5878>] (omap_iommu_save_ctx+0x1c/0x24) from
> [<c027f39c>] (omap3isp_put+0x84/0xfc)
> [    3.444519] [<c027f39c>] (omap3isp_put+0x84/0xfc) from [<c0392b64>]
> (isp_probe+0x8d8/0xa60)
> [    3.453186] [<c0392b64>] (isp_probe+0x8d8/0xa60) from [<c01fa72c>]
> (platform_drv_probe+0x14/0x18)
> [    3.462402] [<c01fa72c>] (platform_drv_probe+0x14/0x18) from [<c01f982c>]
> (driver_probe_device+0xb0/0x1dc)
> 
> compare isp_remove(): isp->domain is set to NULL after iommu_domain_free()
> 
> above crash is observed with 3.7
> the issue is fixed in 3.11 (7c0f812a5d65e712618af880dda4a5cc7ed79463),
> but present in 3.10 longterm

Would cherry-picking commit 7c0f812a5d65e712618af880dda4a5cc7ed79463 for the 
3.10 stable series make sense instead ? Otherwise,

Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> Cc: stable@vger.kernel.org
> Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
> ---
>  drivers/media/platform/omap3isp/isp.c |    1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/media/platform/omap3isp/isp.c
> b/drivers/media/platform/omap3isp/isp.c index 1d7dbd5..a73d9d9 100644
> --- a/drivers/media/platform/omap3isp/isp.c
> +++ b/drivers/media/platform/omap3isp/isp.c
> @@ -2287,6 +2287,7 @@ detach_dev:
>  	iommu_detach_device(isp->domain, &pdev->dev);
>  free_domain:
>  	iommu_domain_free(isp->domain);
> +	isp->domain = NULL;
>  error_isp:
>  	isp_xclk_cleanup(isp);
>  	omap3isp_put(isp);

-- 
Regards,

Laurent Pinchart