Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753485AbbEHU7I (ORCPT ); Fri, 8 May 2015 16:59:08 -0400 Received: from mail-oi0-f43.google.com ([209.85.218.43]:35228 "EHLO mail-oi0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751097AbbEHU7E (ORCPT ); Fri, 8 May 2015 16:59:04 -0400 MIME-Version: 1.0 In-Reply-To: <20150508171955.GA38039@dtor-ws> References: <1431074863-19124-1-git-send-email-geert+renesas@glider.be> <20150508171955.GA38039@dtor-ws> Date: Fri, 8 May 2015 22:59:04 +0200 X-Google-Sender-Auth: 5KtYRayww5UkRNFcKlpHDpFHU1Q Message-ID: Subject: Re: [PATCH] PM / clock_ops: Fix clock error check in __pm_clk_add() From: Geert Uytterhoeven To: Dmitry Torokhov Cc: Geert Uytterhoeven , "Rafael J. Wysocki" , Grygorii Strashko , Kevin Hilman , Santosh Shilimkar , Linux PM list , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2472 Lines: 61 On Fri, May 8, 2015 at 7:19 PM, Dmitry Torokhov wrote: > 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 __clk_get() does the NULL check. > 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 Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds -- 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/