It is possible to call clk_set_rate on a clock with a NULL parent. One
such example is an adjustable-rate root clock. Ensure that
clk_calc_new_rates does not dereference parent without checking first
and also handle the corner cases gracefully.
Reported-by: Rajendra Nayak <rna...@ti.com>
Signed-off-by: Mike Turquette <mturque...@linaro.org>
Cc: Arnd Bergman <arnd.bergm...@linaro.org>
Cc: Olof Johansson <o...@lixom.net>
Cc: Russell King <li...@arm.linux.org.uk>
Cc: Sascha Hauer <s.ha...@pengutronix.de>
Cc: Shawn Guo <shawn....@freescale.com>
Cc: Richard Zhao <richard.z...@linaro.org>
Cc: Saravana Kannan <skan...@codeaurora.org>
Cc: Mark Brown <broo...@opensource.wolfsonmicro.com>
Cc: Andrew Lunn <and...@lunn.ch>
Cc: Viresh Kumar <viresh.ku...@st.com>
---
drivers/clk/clk.c | 29 +++++++++++++++++++++--------
1 files changed, 21 insertions(+), 8 deletions(-)
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 4daacf5..d83a9e0 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -763,25 +763,38 @@ static void clk_calc_subtree(struct clk *clk, unsigned
long new_rate)
static struct clk *clk_calc_new_rates(struct clk *clk, unsigned long rate)
{
struct clk *top = clk;
- unsigned long best_parent_rate = clk->parent->rate;
+ unsigned long best_parent_rate;
unsigned long new_rate;
- if (!clk->ops->round_rate && !(clk->flags & CLK_SET_RATE_PARENT)) {
- clk->new_rate = clk->rate;
+ /* sanity */
+ if (IS_ERR_OR_NULL(clk))
+ return NULL;
+
+ /* never propagate up to the parent */
+ if (!(clk->flags & CLK_SET_RATE_PARENT)) {
+ if (!clk->ops->round_rate) {
+ clk->new_rate = clk->rate;
+ return NULL;
+ } else {
+ new_rate = clk->ops->round_rate(clk->hw, rate, NULL);
+ goto out;
+ }
+ }
+
+ /* need clk->parent from here on out */
+ if (!clk->parent) {
+ pr_debug("%s: %s has NULL parent\n", __func__, clk->name);
return NULL;
}
- if (!clk->ops->round_rate && (clk->flags & CLK_SET_RATE_PARENT)) {
+ if (!clk->ops->round_rate) {
top = clk_calc_new_rates(clk->parent, rate);
new_rate = clk->new_rate = clk->parent->new_rate;
goto out;
}
- if (clk->flags & CLK_SET_RATE_PARENT)
- new_rate = clk->ops->round_rate(clk->hw, rate,
&best_parent_rate);
- else
- new_rate = clk->ops->round_rate(clk->hw, rate, NULL);
+ new_rate = clk->ops->round_rate(clk->hw, rate, &best_parent_rate);
if (best_parent_rate != clk->parent->rate) {
top = clk_calc_new_rates(clk->parent, best_parent_rate);
--
1.7.5.4
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