Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932356AbbEHRUD (ORCPT ); Fri, 8 May 2015 13:20:03 -0400 Received: from mail-ig0-f178.google.com ([209.85.213.178]:37935 "EHLO mail-ig0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932298AbbEHRUA (ORCPT ); Fri, 8 May 2015 13:20:00 -0400 Date: Fri, 8 May 2015 10:19:55 -0700 From: Dmitry Torokhov To: Geert Uytterhoeven Cc: "Rafael J. Wysocki" , Grygorii Strashko , Kevin Hilman , Santosh Shilimkar , linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] PM / clock_ops: Fix clock error check in __pm_clk_add() Message-ID: <20150508171955.GA38039@dtor-ws> References: <1431074863-19124-1-git-send-email-geert+renesas@glider.be> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1431074863-19124-1-git-send-email-geert+renesas@glider.be> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1892 Lines: 51 On Fri, May 08, 2015 at 10:47:43AM +0200, Geert Uytterhoeven wrote: > In the final iteration of commit 245bd6f6af8a62a2 ("PM / clock_ops: Add > pm_clk_add_clk()"), a refcount increment was added by Grygorii Strashko. > However, the accompanying IS_ERR() check operates on the wrong clock > pointer, which is always zero at this point, i.e. not an error. > This may lead to a NULL pointer dereference later, when __clk_get() > tries to dereference an error pointer. > > Check the passed clock pointer instead to fix this. Frankly I would remove the check altogether. Why do we only check for IS_ERR and not NULL or otherwise validate the pointer? The clk is passed in and we do not call any API that would return ERR_PTR-encoded value to us so we shoud lnot even try to handle IS_ERR here. > > Signed-off-by: Geert Uytterhoeven > Fixes: 245bd6f6af8a62a2 ("PM / clock_ops: Add pm_clk_add_clk()") > --- > Note that there are no users of pm_clk_add_clk() in next-20150508, so > for now no in-tree code is affected. > --- > drivers/base/power/clock_ops.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/base/power/clock_ops.c b/drivers/base/power/clock_ops.c > index 7fdd0172605afe1b..c7b0fcebf168cabe 100644 > --- a/drivers/base/power/clock_ops.c > +++ b/drivers/base/power/clock_ops.c > @@ -93,7 +93,7 @@ static int __pm_clk_add(struct device *dev, const char *con_id, > return -ENOMEM; > } > } else { > - if (IS_ERR(ce->clk) || !__clk_get(clk)) { > + if (IS_ERR(clk) || !__clk_get(clk)) { > kfree(ce); > return -ENOENT; > } > -- > 1.9.1 > Thanks. -- Dmitry -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/