[PATCH] clk: Correct handling of NULL clk in __clk_{get, put}

Sylwester Nawrocki
2014-01-07T12:04:19Z

Ensure clk->kref is dereferenced only when clk is not NULL.

Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
---
Hi Sachin,

please try if this patch fixes the exyno5420 boot crash.

Thanks,
Sylwester

drivers/clk/clk.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index e3e0327..a1fe86f 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -2179,24 +2179,25 @@ EXPORT_SYMBOL_GPL(devm_clk_unregister);
*/
int __clk_get(struct clk *clk)
{
- if (clk && !try_module_get(clk->owner))
- return 0;
+ if (clk) {
+ if (!try_module_get(clk->owner))
+ return 0;

- kref_get(&clk->ref);
+ kref_get(&clk->ref);
+ }
return 1;
}

void __clk_put(struct clk *clk)
{
- if (WARN_ON_ONCE(IS_ERR(clk)))
+ if (!clk || WARN_ON_ONCE(IS_ERR(clk)))
return;

clk_prepare_lock();
kref_put(&clk->ref, __clk_release);
clk_prepare_unlock();

- if (clk)
- module_put(clk->owner);
+ module_put(clk->owner);
}

/*** clk rate change notifiers ***/
--
1.7.9.5