From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752788Ab2JVJUu (ORCPT ); Mon, 22 Oct 2012 05:20:50 -0400 Received: from zmc.proxad.net ([212.27.53.206]:45147 "EHLO zmc.proxad.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751125Ab2JVJUs (ORCPT ); Mon, 22 Oct 2012 05:20:48 -0400 From: Florian Fainelli To: cbouatmailru@gmail.com Cc: ccross@android.com, keescook@chromium.org, tony.luck@intel.com, linux-kernel@vger.kernel.org, Maxime Bizon , stable@vger.kernel.org, Florian Fainelli Subject: [PATCH v2] pstore/ram: fix undefined usage of rounddown_pow_of_two(0) Date: Mon, 22 Oct 2012 11:19:28 +0200 Message-Id: <1350897568-14262-1-git-send-email-ffainelli@freebox.fr> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1350647942-5260-1-git-send-email-ffainelli@freebox.fr> References: <1350647942-5260-1-git-send-email-ffainelli@freebox.fr> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Maxime Bizon record_size / console_size / ftrace_size can be 0 (this is how you disable the feature), but rounddown_pow_of_two(0) is undefined. As suggested by Kees Cook, use !is_power_of_2() as a condition to call rounddown_pow_of_two and avoid its undefined behavior on the value 0. This issue has been present since commit 1894a253 (ramoops: Move to fs/pstore/ram.c). CC: stable@vger.kernel.org Signed-off-by: Maxime Bizon Signed-off-by: Florian Fainelli --- Changes since v1: - use !is_power_of_2(size) instead of (!size) fs/pstore/ram.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c index 1a4f6da..bdd840d 100644 --- a/fs/pstore/ram.c +++ b/fs/pstore/ram.c @@ -374,10 +374,14 @@ static int __devinit ramoops_probe(struct platform_device *pdev) goto fail_out; } - pdata->mem_size = rounddown_pow_of_two(pdata->mem_size); - pdata->record_size = rounddown_pow_of_two(pdata->record_size); - pdata->console_size = rounddown_pow_of_two(pdata->console_size); - pdata->ftrace_size = rounddown_pow_of_two(pdata->ftrace_size); + if (!is_power_of_2(pdata->mem_size)) + pdata->mem_size = rounddown_pow_of_two(pdata->mem_size); + if (!is_power_of_2(pdata->record_size)) + pdata->record_size = rounddown_pow_of_two(pdata->record_size); + if (!is_power_of_2(pdata->console_size)) + pdata->console_size = rounddown_pow_of_two(pdata->console_size); + if (!is_power_of_2(pdata->ftrace_size)) + pdata->ftrace_size = rounddown_pow_of_two(pdata->ftrace_size); cxt->dump_read_cnt = 0; cxt->size = pdata->mem_size; -- 1.7.9.5