| Message ID | 1446044628-16924-1-git-send-email-geert+renesas@glider.be (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 8b27418f300cafbdbbb8cfa9c29d398ed34d6723 |
| Headers | show |
Hi Geert > If the "clock-frequency" DT property is not found, req_rate is used > uninitialized, and the "audio_clkout" clock will be created with an > arbitrary clock rate. > > This uninitialized kernel stack data may leak to userspace through > /sys/kernel/debug/clk/clk_summary, cfr. the value in the "rate" column: > > clock enable_cnt prepare_cnt rate accuracy phase > -------------------------------------------------------------------- > audio_clkout 0 0 4001836240 0 0 > > Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> > --- Acked-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> > Should the absence of this property be considered an error? > > Documentation/devicetree/bindings/sound/renesas,rsnd.txt states that > both "#clock-cells" and "clock-frequency" are required properties, but > none of the R-Car Gen1 and Gen2 DTSes seem to have them? This clkout is option for each board will fix
On Wed, Oct 28, 2015 at 04:03:48PM +0100, Geert Uytterhoeven wrote: > If the "clock-frequency" DT property is not found, req_rate is used > uninitialized, and the "audio_clkout" clock will be created with an > arbitrary clock rate. I'd expect that if we support a missing clock frequency property we'd read the state back from the hardware.
diff --git a/sound/soc/sh/rcar/adg.c b/sound/soc/sh/rcar/adg.c index 2a5b3a293cd243db..b123734f9fbdabd9 100644 --- a/sound/soc/sh/rcar/adg.c +++ b/sound/soc/sh/rcar/adg.c @@ -437,7 +437,7 @@ static void rsnd_adg_get_clkout(struct rsnd_priv *priv, struct device *dev = rsnd_priv_to_dev(priv); struct device_node *np = dev->of_node; u32 ckr, rbgx, rbga, rbgb; - u32 rate, req_rate, div; + u32 rate, req_rate = 0, div; uint32_t count = 0; unsigned long req_48kHz_rate, req_441kHz_rate; int i;
If the "clock-frequency" DT property is not found, req_rate is used uninitialized, and the "audio_clkout" clock will be created with an arbitrary clock rate. This uninitialized kernel stack data may leak to userspace through /sys/kernel/debug/clk/clk_summary, cfr. the value in the "rate" column: clock enable_cnt prepare_cnt rate accuracy phase -------------------------------------------------------------------- audio_clkout 0 0 4001836240 0 0 Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> --- Should the absence of this property be considered an error? Documentation/devicetree/bindings/sound/renesas,rsnd.txt states that both "#clock-cells" and "clock-frequency" are required properties, but none of the R-Car Gen1 and Gen2 DTSes seem to have them? --- sound/soc/sh/rcar/adg.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)