clk: add missing lock when call clk_core_enable in clk_set_parent (d2a5d46b) · Commits · 戴 / test

Before commit ("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 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: ("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>

drivers/clk/clk.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -1475,8 +1475,10 @@ static struct clk_core __clk_set_parent_before(struct clk_core clk,
		*/
		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 @@ static void __clk_set_parent_after(struct clk_core *core,
		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 @@ static int __clk_set_parent(struct clk_core clk, struct clk_core parent,
		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;

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