From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761756Ab2DLBIf (ORCPT ); Wed, 11 Apr 2012 21:08:35 -0400 Received: from comal.ext.ti.com ([198.47.26.152]:43191 "EHLO comal.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761732Ab2DLBIb (ORCPT ); Wed, 11 Apr 2012 21:08:31 -0400 From: Mike Turquette To: CC: , , , , Mike Turquette , Olof Johansson , Russell King , Sascha Hauer , Shawn Guo , Richard Zhao , Saravana Kannan , Mark Brown , Andrew Lunn , Viresh Kumar Subject: [PATCH 03/13] clk: core: clk_calc_new_rates handles NULL parents Date: Wed, 11 Apr 2012 18:02:41 -0700 Message-ID: <1334192572-12499-4-git-send-email-mturquette@linaro.org> X-Mailer: git-send-email 1.7.5.4 In-Reply-To: <1334192572-12499-1-git-send-email-mturquette@linaro.org> References: <1334192572-12499-1-git-send-email-mturquette@linaro.org> 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 It is possible to call clk_set_rate on a clock with a NULL parent. One such example is an adjustable-rate root clock. Ensure that clk_calc_new_rates does not dereference parent without checking first and also handle the corner cases gracefully. Reported-by: Rajendra Nayak Signed-off-by: Mike Turquette Cc: Arnd Bergman Cc: Olof Johansson Cc: Russell King Cc: Sascha Hauer Cc: Shawn Guo Cc: Richard Zhao Cc: Saravana Kannan Cc: Mark Brown Cc: Andrew Lunn Cc: Viresh Kumar --- drivers/clk/clk.c | 29 +++++++++++++++++++++-------- 1 files changed, 21 insertions(+), 8 deletions(-) diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index 4daacf5..d83a9e0 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -763,25 +763,38 @@ static void clk_calc_subtree(struct clk *clk, unsigned long new_rate) static struct clk *clk_calc_new_rates(struct clk *clk, unsigned long rate) { struct clk *top = clk; - unsigned long best_parent_rate = clk->parent->rate; + unsigned long best_parent_rate; unsigned long new_rate; - if (!clk->ops->round_rate && !(clk->flags & CLK_SET_RATE_PARENT)) { - clk->new_rate = clk->rate; + /* sanity */ + if (IS_ERR_OR_NULL(clk)) + return NULL; + + /* never propagate up to the parent */ + if (!(clk->flags & CLK_SET_RATE_PARENT)) { + if (!clk->ops->round_rate) { + clk->new_rate = clk->rate; + return NULL; + } else { + new_rate = clk->ops->round_rate(clk->hw, rate, NULL); + goto out; + } + } + + /* need clk->parent from here on out */ + if (!clk->parent) { + pr_debug("%s: %s has NULL parent\n", __func__, clk->name); return NULL; } - if (!clk->ops->round_rate && (clk->flags & CLK_SET_RATE_PARENT)) { + if (!clk->ops->round_rate) { top = clk_calc_new_rates(clk->parent, rate); new_rate = clk->new_rate = clk->parent->new_rate; goto out; } - if (clk->flags & CLK_SET_RATE_PARENT) - new_rate = clk->ops->round_rate(clk->hw, rate, &best_parent_rate); - else - new_rate = clk->ops->round_rate(clk->hw, rate, NULL); + new_rate = clk->ops->round_rate(clk->hw, rate, &best_parent_rate); if (best_parent_rate != clk->parent->rate) { top = clk_calc_new_rates(clk->parent, best_parent_rate); -- 1.7.5.4