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 A9366C433EF for ; Tue, 28 Jun 2022 07:26:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242516AbiF1H0W (ORCPT ); Tue, 28 Jun 2022 03:26:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56956 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242568AbiF1H0R (ORCPT ); Tue, 28 Jun 2022 03:26:17 -0400 Received: from madras.collabora.co.uk (madras.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e5ab]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BD7D22CE24 for ; Tue, 28 Jun 2022 00:26:15 -0700 (PDT) Received: from localhost (unknown [IPv6:2a01:e0a:2c:6930:5cf4:84a1:2763:fe0d]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: bbrezillon) by madras.collabora.co.uk (Postfix) with ESMTPSA id 85B676601856; Tue, 28 Jun 2022 08:26:13 +0100 (BST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1656401174; bh=suXARUlqolSyiyZzoBq0PQIQXSuftLrXkHbx60ZkKso=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=IscQs1pzPwiYacCIUqogKrTu3P8hiBbpw8TUGn93rSNP11fK3wIz2twuEs2rqGIPC 80B7a1NTWSR1s8R4fxMFsD7Jth9FZzwUdvyQkoqKM0hyF6wES3zYGYlh4LKs/kUWOl c+UUspNmbbaX3Eordg//GgNxwKxoGqs4zLiZfFpGVIQF2CTuQZykVbQd/S6G2LtY2f 0N0FETqRjQ5FmWmouE6KCAX5Cj1A7tZ4V79evdz+cBGqmIuZxn/rpUoC+1BRYMjErx KOpR3utIc7tYjtFl1yQnhe/f8QWtqnMDUVuPi+nhyUmsJqDnboABR41WX9FhuuAM9T jPiyjrFtxtUZg== Date: Tue, 28 Jun 2022 09:26:09 +0200 From: Boris Brezillon To: Dan Carpenter Cc: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Daniel Vetter , Jernej Skrabec , Neil Armstrong , dri-devel@lists.freedesktop.org, kernel-janitors@vger.kernel.org Subject: Re: [PATCH] drm/bridge: Avoid uninitialized variable warning Message-ID: <20220628092609.7d0b1ea3@collabora.com> In-Reply-To: References: Organization: Collabora X-Mailer: Claws Mail 4.1.0 (GTK 3.24.34; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: kernel-janitors@vger.kernel.org On Tue, 28 Jun 2022 09:59:51 +0300 Dan Carpenter wrote: > This works, but technically it uses "num_in_bus_fmts" before it has been > initialized so it leads to static checker warnings and probably KMEMsan > warnings at run time. Reverse the checks so it checks for failure first > and then check for unsupported formats next. > > Fixes: f32df58acc68 ("drm/bridge: Add the necessary bits to support bus format negotiation") > Signed-off-by: Dan Carpenter > --- > drivers/gpu/drm/drm_bridge.c | 12 ++++++------ > 1 file changed, 6 insertions(+), 6 deletions(-) > > diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c > index e275b4ca344b..00cbde654472 100644 > --- a/drivers/gpu/drm/drm_bridge.c > +++ b/drivers/gpu/drm/drm_bridge.c > @@ -897,10 +897,10 @@ static int select_bus_fmt_recursive(struct drm_bridge *first_bridge, > conn_state, > out_bus_fmt, > &num_in_bus_fmts); > - if (!num_in_bus_fmts) > - return -ENOTSUPP; > - else if (!in_bus_fmts) > + if (!in_bus_fmts) > return -ENOMEM; > + else if (!num_in_bus_fmts) > + return -ENOTSUPP; Well, it changes the error we return when num_in_bus_fmts = 0 && in_bus_fmts == NULL which is not an ENOMEM situation, so I'd rather initialize num_{in,out}_bus_fmts to 0 here. > > if (first_bridge == cur_bridge) { > cur_state->input_bus_cfg.format = in_bus_fmts[0]; > @@ -993,10 +993,10 @@ drm_atomic_bridge_chain_select_bus_fmts(struct drm_bridge *bridge, > crtc_state, > conn_state, > &num_out_bus_fmts); > - if (!num_out_bus_fmts) > - return -ENOTSUPP; > - else if (!out_bus_fmts) > + if (!out_bus_fmts) > return -ENOMEM; > + else if (!num_out_bus_fmts) > + return -ENOTSUPP; > } else { > num_out_bus_fmts = 1; > out_bus_fmts = kmalloc(sizeof(*out_bus_fmts), GFP_KERNEL); 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 5CE47CCA479 for ; Tue, 28 Jun 2022 07:26:18 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 7440E11B775; Tue, 28 Jun 2022 07:26:17 +0000 (UTC) Received: from madras.collabora.co.uk (madras.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e5ab]) by gabe.freedesktop.org (Postfix) with ESMTPS id 6BB1711B76C for ; Tue, 28 Jun 2022 07:26:15 +0000 (UTC) Received: from localhost (unknown [IPv6:2a01:e0a:2c:6930:5cf4:84a1:2763:fe0d]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: bbrezillon) by madras.collabora.co.uk (Postfix) with ESMTPSA id 85B676601856; Tue, 28 Jun 2022 08:26:13 +0100 (BST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1656401174; bh=suXARUlqolSyiyZzoBq0PQIQXSuftLrXkHbx60ZkKso=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=IscQs1pzPwiYacCIUqogKrTu3P8hiBbpw8TUGn93rSNP11fK3wIz2twuEs2rqGIPC 80B7a1NTWSR1s8R4fxMFsD7Jth9FZzwUdvyQkoqKM0hyF6wES3zYGYlh4LKs/kUWOl c+UUspNmbbaX3Eordg//GgNxwKxoGqs4zLiZfFpGVIQF2CTuQZykVbQd/S6G2LtY2f 0N0FETqRjQ5FmWmouE6KCAX5Cj1A7tZ4V79evdz+cBGqmIuZxn/rpUoC+1BRYMjErx KOpR3utIc7tYjtFl1yQnhe/f8QWtqnMDUVuPi+nhyUmsJqDnboABR41WX9FhuuAM9T jPiyjrFtxtUZg== Date: Tue, 28 Jun 2022 09:26:09 +0200 From: Boris Brezillon To: Dan Carpenter Subject: Re: [PATCH] drm/bridge: Avoid uninitialized variable warning Message-ID: <20220628092609.7d0b1ea3@collabora.com> In-Reply-To: References: Organization: Collabora X-Mailer: Claws Mail 4.1.0 (GTK 3.24.34; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit 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: Thomas Zimmermann , Neil Armstrong , David Airlie , kernel-janitors@vger.kernel.org, dri-devel@lists.freedesktop.org, Jernej Skrabec Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Tue, 28 Jun 2022 09:59:51 +0300 Dan Carpenter wrote: > This works, but technically it uses "num_in_bus_fmts" before it has been > initialized so it leads to static checker warnings and probably KMEMsan > warnings at run time. Reverse the checks so it checks for failure first > and then check for unsupported formats next. > > Fixes: f32df58acc68 ("drm/bridge: Add the necessary bits to support bus format negotiation") > Signed-off-by: Dan Carpenter > --- > drivers/gpu/drm/drm_bridge.c | 12 ++++++------ > 1 file changed, 6 insertions(+), 6 deletions(-) > > diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c > index e275b4ca344b..00cbde654472 100644 > --- a/drivers/gpu/drm/drm_bridge.c > +++ b/drivers/gpu/drm/drm_bridge.c > @@ -897,10 +897,10 @@ static int select_bus_fmt_recursive(struct drm_bridge *first_bridge, > conn_state, > out_bus_fmt, > &num_in_bus_fmts); > - if (!num_in_bus_fmts) > - return -ENOTSUPP; > - else if (!in_bus_fmts) > + if (!in_bus_fmts) > return -ENOMEM; > + else if (!num_in_bus_fmts) > + return -ENOTSUPP; Well, it changes the error we return when num_in_bus_fmts = 0 && in_bus_fmts == NULL which is not an ENOMEM situation, so I'd rather initialize num_{in,out}_bus_fmts to 0 here. > > if (first_bridge == cur_bridge) { > cur_state->input_bus_cfg.format = in_bus_fmts[0]; > @@ -993,10 +993,10 @@ drm_atomic_bridge_chain_select_bus_fmts(struct drm_bridge *bridge, > crtc_state, > conn_state, > &num_out_bus_fmts); > - if (!num_out_bus_fmts) > - return -ENOTSUPP; > - else if (!out_bus_fmts) > + if (!out_bus_fmts) > return -ENOMEM; > + else if (!num_out_bus_fmts) > + return -ENOTSUPP; > } else { > num_out_bus_fmts = 1; > out_bus_fmts = kmalloc(sizeof(*out_bus_fmts), GFP_KERNEL);