Linux Kernel: PM / clk: Fix clock error check in __pm_clk_add()

This change “PM / clk: Fix clock error check in __pm_clk_add()” (commit 3fc3a0b) in Linux kernel is authored by Geert Uytterhoeven <geert+renesas [at] glider.be> on Fri May 8 10:47:43 2015 +0200.

Description of “PM / clk: Fix clock error check in __pm_clk_add()”

The change “PM / clk: Fix clock error check in __pm_clk_add()” introduces changes as follows.

PM / clk: Fix clock error check in __pm_clk_add()

In the final iteration of commit 245bd6f6af8a62a2 ("PM / clock_ops: Add
pm_clk_add_clk()"), a refcount increment was added by Grygorii Strashko.
However, the accompanying IS_ERR() check operates on the wrong clock
pointer, which is always zero at this point, i.e. not an error.
This may lead to a NULL pointer dereference later, when __clk_get()
tries to dereference an error pointer.

Check the passed clock pointer instead to fix this.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Fixes: 245bd6f6af8a62a2 ("PM / clock_ops: Add pm_clk_add_clk()")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Linux kernel code changes from “PM / clk: Fix clock error check in __pm_clk_add()”

There are 2 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 drivers/base/power/clock_ops.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/base/power/clock_ops.c b/drivers/base/power/clock_ops.c
index 8abea669c82c..442ce010559b 100644
--- a/drivers/base/power/clock_ops.c
+++ b/drivers/base/power/clock_ops.c
@@ -94,7 +94,7 @@ static int __pm_clk_add(struct device *dev, const char *con_id,
            return -ENOMEM;
        }
    } else {
-       if (IS_ERR(ce->clk) || !__clk_get(clk)) {
+       if (IS_ERR(clk) || !__clk_get(clk)) {
            kfree(ce);
            return -ENOENT;
        }

The commit for this change in Linux stable tree is 3fc3a0b (patch).