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 75AECC7EE30 for ; Thu, 26 Jun 2025 19:30:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Cc:To:In-Reply-To:References :Message-Id:Content-Transfer-Encoding:Content-Type:MIME-Version:Subject:Date: From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=61C56Q6Ep76yYJPbdXUFIZ1GUL0CTZoCtZck0sPYqq4=; b=v7+/UET6COA2xjpfl2c78Y4MXf HIVrAbZTE5aUOOJG1keCBkPCkg0yMy2zgvNNc9OLP59T9oF62u/Qc+JlnUpY+/LDhXUf4cjMzd4LW W7u7A0iPRn0YLQ0Os6DASWlAkB4rbpczZbDNowFgMuBHoFMZxY6gQ7Vd4lpCtRT9ZvBY1rF08s05e 0NFa4zrcsKZ3xgBrTR5pIuFs5zL9ZgZ0V+HNuvZAxqwK0o8iNXCJIunio74zuNQt4dV8oJSH1PZh/ sSQ54LjYE2eFHJRKvbWLcP846zPu/O2aITqE36FHbiVru1Uazwf8PDgSfo/xYse5Akg+xPfQAhCKH 5XkgwGrA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uUsIR-0000000CZiI-1BqC; Thu, 26 Jun 2025 19:30:07 +0000 Received: from layka.disroot.org ([178.21.23.139]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1uUs9v-0000000CYk5-1zcP for linux-arm-kernel@lists.infradead.org; Thu, 26 Jun 2025 19:21:20 +0000 Received: from mail01.disroot.lan (localhost [127.0.0.1]) by disroot.org (Postfix) with ESMTP id 3CA0825D64; Thu, 26 Jun 2025 21:21:18 +0200 (CEST) X-Virus-Scanned: SPAM Filter at disroot.org Received: from layka.disroot.org ([127.0.0.1]) by localhost (disroot.org [127.0.0.1]) (amavis, port 10024) with ESMTP id IstntXv3cZpE; Thu, 26 Jun 2025 21:21:17 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=disroot.org; s=mail; t=1750965677; bh=D8o5aKxiqPDfJaP/Wlra9wiusUGgyAqkKg4+LuSvXis=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=Pn62ZQw+QE0tjCn0VDNyryMq5NiYYLWChHURVJLwXWY2Rtsz8kcRaMh+VeqrNGfPK QuawYtCEC5pwvYquUJF0BTaMYUdEP8mymD61+I3J8Xi2vCBuYj5GsovKtkj0QKWpcJ SWkHfNKqjS2N/+UHOsL9ZJKWbbnkBf5hR0OTTNwaIr4OY7IxzOxJETsWYDP7jQ8uFV 5DEerlKJvRnt3vZ9+CT63xLNQXw5Jd/E3Tn9H3C4usiVQ7WnH/WkraBe41J2S/gY9A aPvN8jGDGw3u9oyx+EU+4ao2KrmF/gUBkSa5srdyrzqIdNeg7YFct6bsKZaG8tBtQ/ dhC4GJ1vo/jxw== From: Kaustabh Chakraborty Date: Fri, 27 Jun 2025 00:50:30 +0530 Subject: [PATCH v3 3/3] drm/exynos: exynos7_drm_decon: add vblank check in IRQ handling MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20250627-exynosdrm-decon-v3-3-5b456f88cfea@disroot.org> References: <20250627-exynosdrm-decon-v3-0-5b456f88cfea@disroot.org> In-Reply-To: <20250627-exynosdrm-decon-v3-0-5b456f88cfea@disroot.org> To: Inki Dae , Seung-Woo Kim , Kyungmin Park , David Airlie , Simona Vetter , Krzysztof Kozlowski , Alim Akhtar , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Rob Herring , Conor Dooley , Ajay Kumar , Akshu Agrawal , Krzysztof Kozlowski , Conor Dooley Cc: dri-devel@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, Kaustabh Chakraborty , stable@vger.kernel.org X-Developer-Signature: v=1; a=ed25519-sha256; t=1750965633; l=1467; i=kauschluss@disroot.org; s=20250202; h=from:subject:message-id; bh=D8o5aKxiqPDfJaP/Wlra9wiusUGgyAqkKg4+LuSvXis=; b=Zaidk2/MU65T4C2DakEpl1E0vJyg4XwWxX2szoui0qZZcrrbhIkFhB55oDTaWDS1w+QzFykVB dtvzv6gyjheBTohjdUEszCp2rVBomHkZYW6z6n3GgQhxqz5uqjV/bmL X-Developer-Key: i=kauschluss@disroot.org; a=ed25519; pk=h2xeR+V2I1+GrfDPAhZa3M+NWA0Cnbdkkq1bH3ct1hE= X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250626_122119_649534_4B4BFCF7 X-CRM114-Status: GOOD ( 13.03 ) 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org If there's support for another console device (such as a TTY serial), the kernel occasionally panics during boot. The panic message and a relevant snippet of the call stack is as follows: Unable to handle kernel NULL pointer dereference at virtual address 000000000000000 Call trace: drm_crtc_handle_vblank+0x10/0x30 (P) decon_irq_handler+0x88/0xb4 [...] Otherwise, the panics don't happen. This indicates that it's some sort of race condition. Add a check to validate if the drm device can handle vblanks before calling drm_crtc_handle_vblank() to avoid this. Cc: stable@vger.kernel.org Fixes: 96976c3d9aff ("drm/exynos: Add DECON driver") Signed-off-by: Kaustabh Chakraborty --- drivers/gpu/drm/exynos/exynos7_drm_decon.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/gpu/drm/exynos/exynos7_drm_decon.c b/drivers/gpu/drm/exynos/exynos7_drm_decon.c index 43bcbe2e2917df43d7c2d27a9771e892628dd682..c0c0f23169c993ac315fc8d7bcbd09ea6ec9966a 100644 --- a/drivers/gpu/drm/exynos/exynos7_drm_decon.c +++ b/drivers/gpu/drm/exynos/exynos7_drm_decon.c @@ -636,6 +636,10 @@ static irqreturn_t decon_irq_handler(int irq, void *dev_id) if (!ctx->drm_dev) goto out; + /* check if crtc and vblank have been initialized properly */ + if (!drm_dev_has_vblank(ctx->drm_dev)) + goto out; + if (!ctx->i80_if) { drm_crtc_handle_vblank(&ctx->crtc->base); -- 2.49.0