From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756466Ab2GCLNO (ORCPT ); Tue, 3 Jul 2012 07:13:14 -0400 Received: from devils.ext.ti.com ([198.47.26.153]:43675 "EHLO devils.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754298Ab2GCLNN (ORCPT ); Tue, 3 Jul 2012 07:13:13 -0400 From: Rajendra Nayak To: , CC: , , , Rajendra Nayak Subject: [PATCH] clk: fix parent validation in __clk_set_parent() Date: Tue, 3 Jul 2012 16:42:18 +0530 Message-ID: <1341313938-17861-1-git-send-email-rnayak@ti.com> X-Mailer: git-send-email 1.7.1 MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 7975059db572eb47f0fb272a62afeae272a4b209 Author: Rajendra Nayak 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 Signed-off-by: Rajendra Nayak --- drivers/clk/clk.c | 28 +++++++++++++--------------- 1 files changed, 13 insertions(+), 15 deletions(-) diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index 8996f46..46317cb 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -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)) { - if (clk->parents) - clk->parents[i] = __clk_lookup(parent->name); - break; - } + 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", -- 1.7.1