From: Russell King <rmk+ker...@arm.linux.org.uk>
clk_add_alias() calls clk_get() followed by clk_put() but in between
those two calls it saves away the struct clk pointer to a clk_lookup
structure. This leaves the 'clk' member of the clk_lookup pointing at
freed memory on configurations where CONFIG_COMMON_CLK=y. This is a
problem because clk_get_sys() will eventually try to dereference the
freed pointer by calling __clk_get_hw() on it. Fix this by saving away
the struct clk_hw pointer instead of the struct clk pointer so that when
we try to create a per-user struct clk in clk_get_sys() we don't
dereference a junk pointer.
Signed-off-by: Russell King <rmk+ker...@arm.linux.org.uk>
(cherry picked from commit d5622a9c13752be46e6fcde9d31391ce0bb0598b)
Signed-off-by: Yong, Jonathan <jonathan.y...@intel.com>
---
drivers/clk/clkdev.c | 24 ++++++++++++++++--------
include/linux/clkdev.h | 1 +
2 files changed, 17 insertions(+), 8 deletions(-)
diff --git a/drivers/clk/clkdev.c b/drivers/clk/clkdev.c
index 1fcb6ef..1bb120a 100644
--- a/drivers/clk/clkdev.c
+++ b/drivers/clk/clkdev.c
@@ -177,7 +177,7 @@ struct clk *clk_get_sys(const char *dev_id, const char
*con_id)
if (!cl)
goto out;
- clk = __clk_create_clk(__clk_get_hw(cl->clk), dev_id, con_id);
+ clk = __clk_create_clk(cl->clk_hw, dev_id, con_id);
if (IS_ERR(clk))
goto out;
@@ -215,18 +215,26 @@ void clk_put(struct clk *clk)
}
EXPORT_SYMBOL(clk_put);
-void clkdev_add(struct clk_lookup *cl)
+static void __clkdev_add(struct clk_lookup *cl)
{
mutex_lock(&clocks_mutex);
list_add_tail(&cl->node, &clocks);
mutex_unlock(&clocks_mutex);
}
+
+void clkdev_add(struct clk_lookup *cl)
+{
+ if (!cl->clk_hw)
+ cl->clk_hw = __clk_get_hw(cl->clk);
+ __clkdev_add(cl);
+}
EXPORT_SYMBOL(clkdev_add);
void __init clkdev_add_table(struct clk_lookup *cl, size_t num)
{
mutex_lock(&clocks_mutex);
while (num--) {
+ cl->clk_hw = __clk_get_hw(cl->clk);
list_add_tail(&cl->node, &clocks);
cl++;
}
@@ -243,7 +251,7 @@ struct clk_lookup_alloc {
};
static struct clk_lookup * __init_refok
-vclkdev_alloc(struct clk *clk, const char *con_id, const char *dev_fmt,
+vclkdev_alloc(struct clk_hw *hw, const char *con_id, const char *dev_fmt,
va_list ap)
{
struct clk_lookup_alloc *cla;
@@ -252,7 +260,7 @@ vclkdev_alloc(struct clk *clk, const char *con_id, const
char *dev_fmt,
if (!cla)
return NULL;
- cla->cl.clk = clk;
+ cla->cl.clk_hw = hw;
if (con_id) {
strlcpy(cla->con_id, con_id, sizeof(cla->con_id));
cla->cl.con_id = cla->con_id;
@@ -273,7 +281,7 @@ clkdev_alloc(struct clk *clk, const char *con_id, const
char *dev_fmt, ...)
va_list ap;
va_start(ap, dev_fmt);
- cl = vclkdev_alloc(clk, con_id, dev_fmt, ap);
+ cl = vclkdev_alloc(__clk_get_hw(clk), con_id, dev_fmt, ap);
va_end(ap);
return cl;
@@ -334,7 +342,7 @@ int clk_register_clkdev(struct clk *clk, const char *con_id,
return PTR_ERR(clk);
va_start(ap, dev_fmt);
- cl = vclkdev_alloc(clk, con_id, dev_fmt, ap);
+ cl = vclkdev_alloc(__clk_get_hw(clk), con_id, dev_fmt, ap);
va_end(ap);
if (!cl)
@@ -365,8 +373,8 @@ int clk_register_clkdevs(struct clk *clk, struct clk_lookup
*cl, size_t num)
return PTR_ERR(clk);
for (i = 0; i < num; i++, cl++) {
- cl->clk = clk;
- clkdev_add(cl);
+ cl->clk_hw = __clk_get_hw(clk);
+ __clkdev_add(cl);
}
return 0;
diff --git a/include/linux/clkdev.h b/include/linux/clkdev.h
index 94bad77..3003afa 100644
--- a/include/linux/clkdev.h
+++ b/include/linux/clkdev.h
@@ -22,6 +22,7 @@ struct clk_lookup {
const char *dev_id;
const char *con_id;
struct clk *clk;
+ struct clk_hw *clk_hw;
};
#define CLKDEV_INIT(d, n, c) \
--
2.4.10
--
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