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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 078EBC6FD1F for ; Tue, 14 Mar 2023 16:09:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=IbeNy/b9k2MSoVuyxwiX7GX7ADhB8SPUxMIDzDfp2xc=; b=rBGi1cESltBuDa LyVo1wDu5UdvfUZsLpFMplwrOWu8EX9Ag+XinFJOLCppdGGWkyulhkEH9vFyh56En3QNY17a/+0Gz cVA2x0ILL38fJZiH8ovmr2c2ELwbG6ra9ZY1T0TDGm0bugQ6ji5L+zaGnHtTVSwNloC/mkKCsNkaV jiDFN03HwSB0eaUMqLIZ9IY7Cd6vWrMwFaauXso6fG2AEQRf61YZ4AA/g/apU9+UZa3+IdCwdmCYY pb4LQlldi3AARL9aga7gvNvou4smqRwu3LPyoLvW7plyXo7abJoVfvgJMJ5ZyBSCO2s1bxFdghwHH aUfZEvK3GC232ZdjzIbQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1pc7CR-00AkPO-0E; Tue, 14 Mar 2023 16:08:31 +0000 Received: from ams.source.kernel.org ([2604:1380:4601:e00::1]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1pc7CN-00AkO2-2G; Tue, 14 Mar 2023 16:08:29 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id EE023B81A1F; Tue, 14 Mar 2023 16:08:25 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6F2D7C4339B; Tue, 14 Mar 2023 16:08:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1678810104; bh=wA9DCnSggZ7AMT9yojgtSsTiqRDWjhLpUyEUud8IvmE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=dAbWryZpUw6TZWSzeXV/L6G7XErOuD5W4Xe6WLiyuLNeL5oEXrwhuvOWjDanp/69q hgoQeZ5BmogcMEB440DbybHqh9Egk7TDdok25Z9tVdHbNLFe3es76W8aPjqv6FZ0wq kUmqHRPOsl67nHr1DQqXGxnXQcqheiprkRAhmfm6xlwY6nN/6z4kGsPjPhaACjCjHk cbEtMPzPOssPONhgcuAWztD9X5JkNuK+AN/wX3wPmtVss/ayeNF1dBIqjd8YBZoe+k BdIy+OoFmSKUHA0dV4YWkvvGdkLgebsG+aJ8geyRfS4suXrOTRHAlII9BwhvPH6i+o sBBgS3bHSLV9g== Date: Tue, 14 Mar 2023 09:08:21 -0700 From: Nathan Chancellor To: Michael Riesch Cc: devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Rob Herring , Krzysztof Kozlowski , Heiko Stuebner , Sandy Huang , David Airlie , Daniel Vetter , Sascha Hauer , kernel test robot , Dan Carpenter , llvm@lists.linux.dev Subject: Re: [PATCH v3 1/6] drm/rockchip: vop2: initialize possible_crtcs properly Message-ID: <20230314160821.GA13416@dev-arch.thelio-3990X> References: <20230124054706.3921383-1-michael.riesch@wolfvision.net> <20230124054706.3921383-2-michael.riesch@wolfvision.net> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20230124054706.3921383-2-michael.riesch@wolfvision.net> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230314_090828_028951_79590039 X-CRM114-Status: GOOD ( 27.27 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Michael, On Tue, Jan 24, 2023 at 06:47:01AM +0100, Michael Riesch wrote: > The variable possible_crtcs is only initialized for primary and > overlay planes. Since the VOP2 driver only supports these plane > types at the moment, the current code is safe. However, in order > to provide a future-proof solution, fix the initialization of > the variable. > > Reported-by: kernel test robot > Reported-by: Dan Carpenter > Signed-off-by: Michael Riesch > --- > v3: > - no changes > v2: > - new patch > > drivers/gpu/drm/rockchip/rockchip_drm_vop2.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c > index 8cecf81a5ae0..374ef821b453 100644 > --- a/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c > +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c > @@ -2322,10 +2322,11 @@ static int vop2_create_crtc(struct vop2 *vop2) > /* change the unused primary window to overlay window */ > win->type = DRM_PLANE_TYPE_OVERLAY; > } > - } > - > - if (win->type == DRM_PLANE_TYPE_OVERLAY) > + } else if (win->type == DRM_PLANE_TYPE_OVERLAY) { > possible_crtcs = (1 << nvps) - 1; > + } else { > + possible_crtcs = 0; > + } > > ret = vop2_plane_init(vop2, win, possible_crtcs); > if (ret) { > -- > 2.30.2 > This patch is now in -next as commit 368419a2d429 ("drm/rockchip: vop2: initialize possible_crtcs properly") and it actually appears to introduce a path where possible_crtcs could be used uninitialized. drivers/gpu/drm/rockchip/rockchip_drm_vop2.c:2316:8: error: variable 'possible_crtcs' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized] if (vp) { ^~ drivers/gpu/drm/rockchip/rockchip_drm_vop2.c:2330:36: note: uninitialized use occurs here ret = vop2_plane_init(vop2, win, possible_crtcs); ^~~~~~~~~~~~~~ drivers/gpu/drm/rockchip/rockchip_drm_vop2.c:2316:4: note: remove the 'if' if its condition is always true if (vp) { ^~~~~~~~ drivers/gpu/drm/rockchip/rockchip_drm_vop2.c:2298:21: note: initialize the variable 'possible_crtcs' to silence this warning u32 possible_crtcs; ^ = 0 1 error generated. Prior to this change, if that else path was hit, clang recognized based on the assignment that the next if statement would always be true. Now, if the else path is taken, the possible_crtcs assignment will be missed. Is that intentional? Cheers, Nathan _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel