clk: Don't try to use a struct clk* after it could have been freed

commit 10cdfe54dab034311c8e2fad9ba2dffbe616caa9 upstream.

As __clk_release could call kfree on clk and then we wouldn't have a safe way
of getting the module that owns the clock.

Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Fixes: fcb0ee6a3d33 ("clk: Implement clk_unregister")
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Michael Turquette <mturquette@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index f9c4632d4dd3b9b2c9ac5fee7c954f7c6b41bdcd..7145f6d93567be08ffaad761e4d1a16f10c048f7 100644 (file)
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -2232,14 +2232,17 @@ int __clk_get(struct clk *clk)
 
 void __clk_put(struct clk *clk)
 {
+       struct module *owner;
+
        if (!clk || WARN_ON_ONCE(IS_ERR(clk)))
                return;
 
        clk_prepare_lock();
+       owner = clk->owner;
        kref_put(&clk->ref, __clk_release);
        clk_prepare_unlock();
 
-       module_put(clk->owner);
+       module_put(owner);
 }
 
 /***        clk rate change notifiers        ***/