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 2B645CD343F for ; Mon, 18 May 2026 19:48:41 +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:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=fkGNzPgLT1Dz0z6nTFi2No6Ifen2fpOCha4Dk4M3oxg=; b=4TjWEkkgqNOIa5I22tiQI/C+U6 WOg86UP6qynRK0vSbIpq4EXEej1dKFvWXAWfcLT0j5YHzz7X72pkEPiYPdQAEypjc4nplTC0Kn1qu HC2dW+3S0orfKgYUyCinSMyctnx+VD8aMrwrzSrfr6tlVzYO/fdTSdut96ImmicxpNX+lmznBQCtp YBA7EQko0m4GGW8k8nI7jktTJiI9g67SNtDU6Sei7r55G+5VA+lvByZECwFx3Zmuk7qUQHdBAxQDO aJH/XJa6ClRDxxccDaITZlU/STLSzY9bErTmICOWK6dRj3V3fZtBrm1pRqSMNMl7u7QjCAtc9cnGQ PAAeKUTw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wP3x4-0000000Glhi-0QE8; Mon, 18 May 2026 19:48:34 +0000 Received: from smtp.forwardemail.net ([149.28.215.223]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wP3wz-0000000GlXP-1ONj for linux-arm-kernel@lists.infradead.org; Mon, 18 May 2026 19:48:30 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kwiboo.se; h=Content-Transfer-Encoding: MIME-Version: References: In-Reply-To: Message-ID: Date: Subject: Cc: To: From; q=dns/txt; s=fe-e1b5cab7be; t=1779133702; bh=fkGNzPgLT1Dz0z6nTFi2No6Ifen2fpOCha4Dk4M3oxg=; b=GQVzrkfA/dN5ou6bbU2oB6I7lxtRgXT/BctJu2Lu4SL9yzUnFpmkopbanCDgSjdxVgJQhIu0B Mv+m+GAiPW4I7P908DUxvvvQZOMKfb93dq3Fix/q4eiqQ0gg48lzm7KE0s7aIFUpzuO5p2pLB3K 6Yeq/2sPh5UIq5e+lxnnMqDo01UdubIor4k3CPRKkxmuPY/aJQ+eRdkr2vylYiRhQB5vITnekxQ uFB2zczjyDtRwhXgmtDsZwPe8SQ1T2p2kwhUHwTwVAKG32y7FgaSWvgGYLaZPULCGaVhuqAnLwZ 5eo/Nu1pOk4JYn/S4iIubxxfMnm9sT28hRYZM6Fd7VBQ== X-Forward-Email-ID: 6a0b6cf1b74b0ebd362eee3b X-Forward-Email-Sender: rfc822; jonas@kwiboo.se, smtp.forwardemail.net, 149.28.215.223 X-Forward-Email-Version: 2.8.12 X-Forward-Email-Website: https://forwardemail.net X-Complaints-To: abuse@forwardemail.net X-Report-Abuse: abuse@forwardemail.net X-Report-Abuse-To: abuse@forwardemail.net From: Jonas Karlman To: Neil Armstrong , Kevin Hilman , Heiko Stuebner , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Jerome Brunet , Martin Blumenstingl , Sam Ravnborg Cc: dri-devel@lists.freedesktop.org, linux-amlogic@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Jonas Karlman , linux-rockchip@lists.infradead.org Subject: [PATCH 02/13] drm/meson: dw-hdmi: Protect from possible NULL pointer dereference Date: Mon, 18 May 2026 19:47:30 +0000 Message-ID: <20260518194744.2483580-3-jonas@kwiboo.se> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260518194744.2483580-1-jonas@kwiboo.se> References: <20260518194744.2483580-1-jonas@kwiboo.se> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260518_124829_380393_45B0073E X-CRM114-Status: GOOD ( 13.13 ) 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 The IRQ handler can be called at any time after the call to devm_request_threaded_irq() completes, even before dw_hdmi->bridge has been assigned later in meson_dw_hdmi_bind(). Protect from a possible NULL pointer dereference in IRQ handler by only calling drm_helper_hpd_irq_event() when bridge has been assigned. Fixes: e67f6037ae1b ("drm/meson: split out encoder from meson_dw_hdmi") Signed-off-by: Jonas Karlman --- I only observed this NULL pointer dereference one time, without being able to reliably re-create a similar timing scenario. I still think this is an issue that possible could happen and likely should be fixed. Note that patches later in this series will fully replace this change. --- drivers/gpu/drm/meson/meson_dw_hdmi.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/meson/meson_dw_hdmi.c b/drivers/gpu/drm/meson/meson_dw_hdmi.c index 993f6d5d4b29..eafe7daf6ff1 100644 --- a/drivers/gpu/drm/meson/meson_dw_hdmi.c +++ b/drivers/gpu/drm/meson/meson_dw_hdmi.c @@ -520,7 +520,8 @@ static irqreturn_t dw_hdmi_top_thread_irq(int irq, void *dev_id) u32 stat = dw_hdmi->irq_stat; /* HPD Events */ - if (stat & (HDMITX_TOP_INTR_HPD_RISE | HDMITX_TOP_INTR_HPD_FALL)) { + if (stat & (HDMITX_TOP_INTR_HPD_RISE | HDMITX_TOP_INTR_HPD_FALL) && + dw_hdmi->bridge) { bool hpd_connected = false; if (stat & HDMITX_TOP_INTR_HPD_RISE) -- 2.54.0