clkdev: Fix race condition in clock lookup from device tree
There is currently a race condition in the device tree part of clk_get() function, since the pointer returned from of_clk_get_by_name() may become invalid before __clk_get() call. E.g. due to the clock provider driver remove() callback being called in between of_clk_get_by_name() and __clk_get(). Fix this by doing both the look up and __clk_get() operations with the clock providers list mutex held. This ensures that the clock pointer returned from __of_clk_get_from_provider() call and passed to __clk_get() is valid, as long as the clock supplier module first removes its clock provider instance and then does clk_unregister() on the corresponding clocks. Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Reviewed-by: Mike Turquette <mturquette@linaro.org> Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
parent
d6782c2636
commit
3a3d2b0551
|
@ -21,6 +21,8 @@
|
|||
#include <linux/clkdev.h>
|
||||
#include <linux/of.h>
|
||||
|
||||
#include "clk.h"
|
||||
|
||||
static LIST_HEAD(clocks);
|
||||
static DEFINE_MUTEX(clocks_mutex);
|
||||
|
||||
|
@ -39,7 +41,13 @@ struct clk *of_clk_get(struct device_node *np, int index)
|
|||
if (rc)
|
||||
return ERR_PTR(rc);
|
||||
|
||||
clk = of_clk_get_from_provider(&clkspec);
|
||||
of_clk_lock();
|
||||
clk = __of_clk_get_from_provider(&clkspec);
|
||||
|
||||
if (!IS_ERR(clk) && !__clk_get(clk))
|
||||
clk = ERR_PTR(-ENOENT);
|
||||
|
||||
of_clk_unlock();
|
||||
of_node_put(clkspec.np);
|
||||
return clk;
|
||||
}
|
||||
|
@ -157,7 +165,7 @@ struct clk *clk_get(struct device *dev, const char *con_id)
|
|||
|
||||
if (dev) {
|
||||
clk = of_clk_get_by_name(dev->of_node, con_id);
|
||||
if (!IS_ERR(clk) && __clk_get(clk))
|
||||
if (!IS_ERR(clk))
|
||||
return clk;
|
||||
}
|
||||
|
||||
|
|
Loading…
Reference in a new issue