[PATCH] media: omap3isp: zero-initialize the isp cam_xclk{a,b} initial data

[PATCH] media: omap3isp: zero-initialize the isp cam_xclk{a,b} initial data

[Javier Martinez Canillas]

The struct clk_init_data defined in isp_xclk_init() is a variable in the
stack but it's not explicitly zero-initialized. Because of that, in some
cases the data structure contains values that confuses the clk framework.

For example if the flags member has the CLK_IS_CRITICAL bit set, the clk
framework will wrongly prepare the clock on registration. This leads to
the isp_xclk_prepare() callback to be called which in turn calls to the
omap3isp_get() function that increments the isp device reference counter.

Since this omap3isp_get() call is unexpected, this leads to an unbalanced
omap3isp_get() call that prevents the requested IRQ to be later enabled,
due the refcount not being 0 when the correct omap3isp_get() call happens.

Fixes: 9b28ee3c9122 ("[media] omap3isp: Use the common clock framework")
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>

---

 drivers/media/platform/omap3isp/isp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/media/platform/omap3isp/isp.c b/drivers/media/platform/omap3isp/isp.c
index f22cf351e3e..ae0ef8b241a 100644
--- a/drivers/media/platform/omap3isp/isp.c
+++ b/drivers/media/platform/omap3isp/isp.c
@@ -300,7 +300,7 @@ static struct clk *isp_xclk_src_get(struct of_phandle_args *clkspec, void *data)
 static int isp_xclk_init(struct isp_device *isp)
 {
 	struct device_node *np = isp->dev->of_node;
-	struct clk_init_data init;
+	struct clk_init_data init = { 0 };
 	unsigned int i;
 
 	for (i = 0; i < ARRAY_SIZE(isp->xclks); ++i)
-- 
2.17.1

Re: [PATCH] media: omap3isp: zero-initialize the isp cam_xclk{a,b} initial data

[Pavel Machek]

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On Sat 2018-06-09 10:39:12, Javier Martinez Canillas wrote:
> The struct clk_init_data defined in isp_xclk_init() is a variable in the
> stack but it's not explicitly zero-initialized. Because of that, in some
> cases the data structure contains values that confuses the clk framework.
> 
> For example if the flags member has the CLK_IS_CRITICAL bit set, the clk
> framework will wrongly prepare the clock on registration. This leads to
> the isp_xclk_prepare() callback to be called which in turn calls to the
> omap3isp_get() function that increments the isp device reference counter.
> 
> Since this omap3isp_get() call is unexpected, this leads to an unbalanced
> omap3isp_get() call that prevents the requested IRQ to be later enabled,
> due the refcount not being 0 when the correct omap3isp_get() call happens.
> 
> Fixes: 9b28ee3c9122 ("[media] omap3isp: Use the common clock framework")
> Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>

Tested-by: Pavel Machek <pavel@ucw.cz>

-- 
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