clk: add missing lock when call clk_core_enable in clk_set_parent
Before commit 035a61c314eb ("clk: Make clk API return per-user
struct clk instances") we acquired the enable_lock in
__clk_set_parent_{before,after}() by means of calling
clk_enable(). After commit 035a61c314eb we use clk_core_enable()
in place of the clk_enable(), and clk_core_enable() doesn't
acquire the enable_lock. This opens up a race condition between
clk_set_parent() and clk_enable(). Fix it.
Fixes: 035a61c314eb ("clk: Make clk API return per-user struct clk instances")
Cc: Mike Turquette <mturquette@linaro.org>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Dong Aisheng <aisheng.dong@freescale.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 459ce9d..5b0f418 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -1475,8 +1475,10 @@
*/
if (clk->prepare_count) {
clk_core_prepare(parent);
+ flags = clk_enable_lock();
clk_core_enable(parent);
clk_core_enable(clk);
+ clk_enable_unlock(flags);
}
/* update the clk tree topology */
@@ -1491,13 +1493,17 @@
struct clk_core *parent,
struct clk_core *old_parent)
{
+ unsigned long flags;
+
/*
* Finish the migration of prepare state and undo the changes done
* for preventing a race with clk_enable().
*/
if (core->prepare_count) {
+ flags = clk_enable_lock();
clk_core_disable(core);
clk_core_disable(old_parent);
+ clk_enable_unlock(flags);
clk_core_unprepare(old_parent);
}
}
@@ -1525,8 +1531,10 @@
clk_enable_unlock(flags);
if (clk->prepare_count) {
+ flags = clk_enable_lock();
clk_core_disable(clk);
clk_core_disable(parent);
+ clk_enable_unlock(flags);
clk_core_unprepare(parent);
}
return ret;