clk: fix parent validation in __clk_set_parent() (863b1327) · Commits · e / devices / android_kernel_fairphone_FP3

The below commit introduced a bug in __clk_set_parent() which could cause it to *skip* the parent validation which makes sure the parent passed to the api is a valid one. commit Author: Rajendra Nayak <rnayak@ti.com> Date: Wed Jun 6 14:41:31 2012 +0530 clk: Allow late cache allocation for clk->parents This was identified by the following compiler warning.. drivers/clk/clk.c: In function '__clk_set_parent': drivers/clk/clk.c:1083:5: warning: 'i' may be used uninitialized in this function [-Wuninitialized] .. as reported by Marc Kleine-Budde. There were various options discussed on how to fix this, one being initing 'i' to clk->num_parents, but the below approach was found to be more appropriate as it also makes the 'parent validation' code simpler to read. Reported-by:

Marc Kleine-Budde <mkl@pengutronix.de> Signed-off-by:

Rajendra Nayak <rnayak@ti.com> Signed-off-by:

Mike Turquette <mturquette@linaro.org> Cc: stable@kernel.org

drivers/clk/clk.c

+13 −15

Original line number	Diff line number	Diff line
		@@ -1067,26 +1067,24 @@ static int __clk_set_parent(struct clk clk, struct clk parent)

		old_parent = clk->parent;

		/* find index of new parent clock using cached parent ptrs */
		if (clk->parents)
		for (i = 0; i < clk->num_parents; i++)
		if (clk->parents[i] == parent)
		break;
		else
		if (!clk->parents)
		clk->parents = kzalloc((sizeof(struct clk) clk->num_parents),
		GFP_KERNEL);

		/*
		* find index of new parent clock using string name comparison
		* also try to cache the parent to avoid future calls to __clk_lookup
		* find index of new parent clock using cached parent ptrs,
		* or if not yet cached, use string name comparison and cache
		* them now to avoid future calls to __clk_lookup.
		*/
		if (i == clk->num_parents)
		for (i = 0; i < clk->num_parents; i++)
		if (!strcmp(clk->parent_names[i], parent->name)) {
		for (i = 0; i < clk->num_parents; i++) {
		if (clk->parents && clk->parents[i] == parent)
		break;
		else if (!strcmp(clk->parent_names[i], parent->name)) {
		if (clk->parents)
		clk->parents[i] = __clk_lookup(parent->name);
		break;
		}
		}

		if (i == clk->num_parents) {
		pr_debug("%s: clock %s is not a possible parent of clock %s\n",