From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id CFA6EC433F5 for ; Wed, 6 Apr 2022 16:23:30 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 2062410E070; Wed, 6 Apr 2022 16:23:30 +0000 (UTC) Received: from mail-wr1-x42f.google.com (mail-wr1-x42f.google.com [IPv6:2a00:1450:4864:20::42f]) by gabe.freedesktop.org (Postfix) with ESMTPS id B198110E070; Wed, 6 Apr 2022 16:23:29 +0000 (UTC) Received: by mail-wr1-x42f.google.com with SMTP id q19so4023568wrc.6; Wed, 06 Apr 2022 09:23:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=J9a2BqBVokvTsgXQbtymYfO3sWscM/hLjb0STJ5+gfo=; b=ZLBha3ufL0jqhFoZzUzSgpHsnHd6DM/HSKIHl7RHPuuFY1C1cWUqC0PfmMqS7DfunJ Dky80ByJLgonPzNihsl2DXLyMlG2HbrxCQsQtCbp92JDX62+0uWXZ/XEN2OUXX5L8okT l+3ZdiwM34ISMZtglwh0Nr/0cU6YMcyjlAOt1fK307cGVY5BMZwtRE/R3iw6kGLLhlYm qSxsiaAwSPmtRYrHmrhSi3H7OUENgEptGKC9vdm2kyX8NrGkbQIIS+4IwvDduTDGpdoQ DigItKzsvp5rE9c8Y9TXEe0Y/CHcbfPrSzNP3deLbKRmbTIW88KJDJJTXX10Ss517V8d iw+A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=J9a2BqBVokvTsgXQbtymYfO3sWscM/hLjb0STJ5+gfo=; b=YfGExkj1wR+QFfL0KKn2e7mLXLfm/WxAD2yo1lh4PLIFeDj50g/u+ZcPnzNUveWoiL iHKGo8efEL4DE+UfZh5FNgDFeLUddsLFqB/IaaqVydPkBRtZc99ABhg550Q9PiBjpSEg GsruKXKTQD7ZqrRF6v9yzgTJDG3qOCAw1VKGj5j66tQtqvahBgxSHpYeg4BUW3jXLdmv Ys9kpJAVN6WXmn4PSPAHytFaZ+mn5ZFZT7P3vMz59H/erRXyIR1Ef6qQ/vks0nUb31yz /QNoz/+rTEqCbKVj76laRw7TMp12R1iClASdR673nLaTHealYrr1iIBk+82CVi+nArcs Bfhg== X-Gm-Message-State: AOAM530V4a6AdTlxfAVfPoYdBR+8TXjxCfw9nwAcqVC0bib9xGpZjInr xp5Npz0Ol0RthXSL35l5whVNh4ronnrMiKZGN2A= X-Google-Smtp-Source: ABdhPJxXoRbU0Fimgs0YJrKVL8vfK3EP/15SjU89Ap7jwE5IFgghAQow9fzCF+kzSvUWRMEQeGazbnjQquNqIPBJoxo= X-Received: by 2002:adf:9111:0:b0:206:c9b:ce0d with SMTP id j17-20020adf9111000000b002060c9bce0dmr7345582wrj.418.1649262207917; Wed, 06 Apr 2022 09:23:27 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Rob Clark Date: Wed, 6 Apr 2022 09:24:22 -0700 Message-ID: Subject: Re: [PATCH] drm/msm/mdp5: check the return of kzalloc() To: xkernel.wang@foxmail.com Content-Type: text/plain; charset="UTF-8" X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Sean Paul , David Airlie , linux-arm-msm , Linux Kernel Mailing List , dri-devel , freedreno Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Thu, Mar 24, 2022 at 1:37 AM wrote: > > From: Xiaoke Wang > > kzalloc() is a memory allocation function which can return NULL when > some internal memory errors happen. So it is better to check it to > prevent potential wrong memory access. > > Signed-off-by: Xiaoke Wang > --- > drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c | 17 ++++++++++------- > 1 file changed, 10 insertions(+), 7 deletions(-) > > diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c b/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c > index c6b69af..5f914cc 100644 > --- a/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c > +++ b/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c > @@ -90,15 +90,18 @@ static void mdp5_plane_reset(struct drm_plane *plane) > __drm_atomic_helper_plane_destroy_state(plane->state); > > kfree(to_mdp5_plane_state(plane->state)); > - mdp5_state = kzalloc(sizeof(*mdp5_state), GFP_KERNEL); > + plane->state = NULL; At this point, you could just: if (!mdp5_state) return; BR, -R > > - if (plane->type == DRM_PLANE_TYPE_PRIMARY) > - mdp5_state->base.zpos = STAGE_BASE; > - else > - mdp5_state->base.zpos = STAGE0 + drm_plane_index(plane); > - mdp5_state->base.normalized_zpos = mdp5_state->base.zpos; > + mdp5_state = kzalloc(sizeof(*mdp5_state), GFP_KERNEL); > + if (mdp5_state) { > + if (plane->type == DRM_PLANE_TYPE_PRIMARY) > + mdp5_state->base.zpos = STAGE_BASE; > + else > + mdp5_state->base.zpos = STAGE0 + drm_plane_index(plane); > + mdp5_state->base.normalized_zpos = mdp5_state->base.zpos; > > - __drm_atomic_helper_plane_reset(plane, &mdp5_state->base); > + __drm_atomic_helper_plane_reset(plane, &mdp5_state->base); > + } > } > > static struct drm_plane_state * > -- From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 78A9EC433FE for ; Wed, 6 Apr 2022 17:46:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239421AbiDFRsh (ORCPT ); Wed, 6 Apr 2022 13:48:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42194 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239925AbiDFRrz (ORCPT ); Wed, 6 Apr 2022 13:47:55 -0400 Received: from mail-wr1-x429.google.com (mail-wr1-x429.google.com [IPv6:2a00:1450:4864:20::429]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A040A10BD22; Wed, 6 Apr 2022 09:23:29 -0700 (PDT) Received: by mail-wr1-x429.google.com with SMTP id k23so4017714wrd.8; Wed, 06 Apr 2022 09:23:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=J9a2BqBVokvTsgXQbtymYfO3sWscM/hLjb0STJ5+gfo=; b=ZLBha3ufL0jqhFoZzUzSgpHsnHd6DM/HSKIHl7RHPuuFY1C1cWUqC0PfmMqS7DfunJ Dky80ByJLgonPzNihsl2DXLyMlG2HbrxCQsQtCbp92JDX62+0uWXZ/XEN2OUXX5L8okT l+3ZdiwM34ISMZtglwh0Nr/0cU6YMcyjlAOt1fK307cGVY5BMZwtRE/R3iw6kGLLhlYm qSxsiaAwSPmtRYrHmrhSi3H7OUENgEptGKC9vdm2kyX8NrGkbQIIS+4IwvDduTDGpdoQ DigItKzsvp5rE9c8Y9TXEe0Y/CHcbfPrSzNP3deLbKRmbTIW88KJDJJTXX10Ss517V8d iw+A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=J9a2BqBVokvTsgXQbtymYfO3sWscM/hLjb0STJ5+gfo=; b=oBf/ACoukip41uS6lNYXOo2BPEWFvaLxYi0r2SAWFWgJtVE9YbQXNzYwPqR5ecavcD QgU146s6OLuZnEvHVrtszRhdsS4XtWICHGGnq9nJ0/ViHaaVflF1eYdXshEpyBieBJyo RIrIFs1AVmNSlvZXdzAjln/Rub23WudyG6WPVHh29dtdBcIMd8fJtlrdCT1zv/WWKXcH mAVHHlAou3G2Ks/vQSyanqvQcHQp1MopJGySOAKziKFchDPFeNea5P4cHuKXFd6RlBN1 I0gaRBOcqk/+q/g4zinXn05YuUzhZfCWg8Ad2v+38lCBTwioYkdnV1Y0JQNcY3K5z9b0 dFRw== X-Gm-Message-State: AOAM533U5SsHMG7mi2ODs8/YJXkkw55LbUjJDAcz7GOsJ/P5nn1F0kT+ Wbo4QlUraTQ5T/kW4+qptw2/M1gC2+xNbukimhpHVi1Y X-Google-Smtp-Source: ABdhPJxXoRbU0Fimgs0YJrKVL8vfK3EP/15SjU89Ap7jwE5IFgghAQow9fzCF+kzSvUWRMEQeGazbnjQquNqIPBJoxo= X-Received: by 2002:adf:9111:0:b0:206:c9b:ce0d with SMTP id j17-20020adf9111000000b002060c9bce0dmr7345582wrj.418.1649262207917; Wed, 06 Apr 2022 09:23:27 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Rob Clark Date: Wed, 6 Apr 2022 09:24:22 -0700 Message-ID: Subject: Re: [PATCH] drm/msm/mdp5: check the return of kzalloc() To: xkernel.wang@foxmail.com Cc: Sean Paul , David Airlie , Daniel Vetter , linux-arm-msm , dri-devel , freedreno , Linux Kernel Mailing List Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On Thu, Mar 24, 2022 at 1:37 AM wrote: > > From: Xiaoke Wang > > kzalloc() is a memory allocation function which can return NULL when > some internal memory errors happen. So it is better to check it to > prevent potential wrong memory access. > > Signed-off-by: Xiaoke Wang > --- > drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c | 17 ++++++++++------- > 1 file changed, 10 insertions(+), 7 deletions(-) > > diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c b/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c > index c6b69af..5f914cc 100644 > --- a/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c > +++ b/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c > @@ -90,15 +90,18 @@ static void mdp5_plane_reset(struct drm_plane *plane) > __drm_atomic_helper_plane_destroy_state(plane->state); > > kfree(to_mdp5_plane_state(plane->state)); > - mdp5_state = kzalloc(sizeof(*mdp5_state), GFP_KERNEL); > + plane->state = NULL; At this point, you could just: if (!mdp5_state) return; BR, -R > > - if (plane->type == DRM_PLANE_TYPE_PRIMARY) > - mdp5_state->base.zpos = STAGE_BASE; > - else > - mdp5_state->base.zpos = STAGE0 + drm_plane_index(plane); > - mdp5_state->base.normalized_zpos = mdp5_state->base.zpos; > + mdp5_state = kzalloc(sizeof(*mdp5_state), GFP_KERNEL); > + if (mdp5_state) { > + if (plane->type == DRM_PLANE_TYPE_PRIMARY) > + mdp5_state->base.zpos = STAGE_BASE; > + else > + mdp5_state->base.zpos = STAGE0 + drm_plane_index(plane); > + mdp5_state->base.normalized_zpos = mdp5_state->base.zpos; > > - __drm_atomic_helper_plane_reset(plane, &mdp5_state->base); > + __drm_atomic_helper_plane_reset(plane, &mdp5_state->base); > + } > } > > static struct drm_plane_state * > --