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clkdev: use clk_hw internally 

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+kernel@arm.linux.org.uk>
This commit is contained in:
Russell King 2015-03-02 15:45:41 +00:00
parent b787f68c36
commit d5622a9c13
2 changed files with 17 additions and 8 deletions
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24
drivers/clk/clkdev.c
View File

@ -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;

1
include/linux/clkdev.h
View File

@ -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) \