Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933879AbcJFTEE (ORCPT ); Thu, 6 Oct 2016 15:04:04 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:42359 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933727AbcJFTEB (ORCPT ); Thu, 6 Oct 2016 15:04:01 -0400 Subject: Re: [PATCH] drm/amd/amdgpu: default to zero number of states if not enabled To: Alex Deucher References: <20161006180211.31747-1-colin.king@canonical.com> Cc: Alex Deucher , =?UTF-8?Q?Christian_K=c3=b6nig?= , David Airlie , Eric Huang , Rex Zhu , Jammy Zhou , Tom St Denis , Dan Carpenter , Maling list - DRI developers , LKML From: Colin Ian King Message-ID: <57F6A01D.10907@canonical.com> Date: Thu, 6 Oct 2016 20:03:57 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1688 Lines: 50 On 06/10/16 19:32, Alex Deucher wrote: > On Thu, Oct 6, 2016 at 2:02 PM, Colin King wrote: >> From: Colin Ian King >> >> Currently, if adev->pp_enabled is false then the pp_stats_info data >> is not read and hence a garbage number of states from the stack >> is used to dump out the number of states. Given data.nums could be >> any random value, this could easily lead to read outside the >> data.states array. Fix this by setting data.nums to zero if >> adev->pp_enabled is false. > > Are you actually seeing a problem? Nope. > The pp_num_states attribute only > gets added in the first place if pp_enabled is true. Does that mean that the check on adev->pp_enabled is redundant then? > > Alex > >> >> Signed-off-by: Colin Ian King >> --- >> drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c | 2 ++ >> 1 file changed, 2 insertions(+) >> >> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c >> index accc908..808d788 100644 >> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c >> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c >> @@ -195,6 +195,8 @@ static ssize_t amdgpu_get_pp_num_states(struct device *dev, >> >> if (adev->pp_enabled) >> amdgpu_dpm_get_pp_num_states(adev, &data); >> + else >> + data.nums = 0; >> >> buf_len = snprintf(buf, PAGE_SIZE, "states: %d\n", data.nums); >> for (i = 0; i < data.nums; i++) >> -- >> 2.9.3 >> >> _______________________________________________ >> dri-devel mailing list >> dri-devel@lists.freedesktop.org >> https://lists.freedesktop.org/mailman/listinfo/dri-devel