From nobody Tue Feb 10 06:07:28 2026 Received: from smtpout-03.galae.net (smtpout-03.galae.net [185.246.85.4]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D06112ED164 for ; Fri, 9 Jan 2026 07:32:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.246.85.4 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767943947; cv=none; b=FAvowFJLwaY9wqIGPXScI+KLjavYuNiaS/LX9p6Vxn+Rt7c9AGJ6oX+zZy7BLqtiXjlYZytYDRIHP1S38VNGK+A13Ck57obXjmMEQchvD3eQrZUgYekW9yZkW4Pr1CMBPD0/Hjd6/VqwM+QvY37qJ1EMaU4ib1ulqN4wSMfJYYE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767943947; c=relaxed/simple; bh=KSL2l9Nhr9MJtBx01zg+IQEWAc+m7BWeTGMVVVLcJCg=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=GtVUgfQHAzNjYCiS8U4HzKf/eMHw7BSwa6vKXwCKI6bIP+lUpq+AsRL8zaZYHMJt0UBMKiTEpEmmL4Tu44foNZOcWfMSv6fNwQ1tKIrakLqvM9Ql231w9BWTXwTkodiNdz5QsybpZT2XQyXqCZx64iAiA/MOU7AmWm60DB9Y2Rw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com; spf=pass smtp.mailfrom=bootlin.com; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b=R9lGI9yu; arc=none smtp.client-ip=185.246.85.4 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bootlin.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b="R9lGI9yu" Received: from smtpout-01.galae.net (smtpout-01.galae.net [212.83.139.233]) by smtpout-03.galae.net (Postfix) with ESMTPS id A0EC54E4201A; Fri, 9 Jan 2026 07:32:24 +0000 (UTC) Received: from mail.galae.net (mail.galae.net [212.83.136.155]) by smtpout-01.galae.net (Postfix) with ESMTPS id 755ED60734; Fri, 9 Jan 2026 07:32:24 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id 9C88A103C87E8; Fri, 9 Jan 2026 08:32:19 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=dkim; t=1767943943; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding:in-reply-to:references; bh=u2y2VqIJAA06H1k3L5bHNZmoiLt8l/HcFcKFwhue0ts=; b=R9lGI9yuKuRCVLqejCsbPo6uvVI4QMrNJR7s37pp2V9gRBFkHEVlU9BAS9VH1mH80ED1lq CO6/jZ8H6sDZRdxvw0SbYVQ5UfUt0RyCZP0zm9eF58tziBhxZ0HhPu/60A9xdlG5g0YuHE MkTfeIERWYHfWDA/rEkBg2h/k+IeO+dHREaoQdRK5hBNZ6VStXYZyYL1MSblClJS8l6ZmX arWj+84HshE3IJzyHLeOK+7R7aY0/upR/wMKxuJNPGvQuF9h89AS5xsMJ90y3GK9rpvgny bextH8LFCOa8lt0bQCa6xjk76zVCSB1jvVUIDYhw3esXwqhixu0LsfRxrw471Q== From: Luca Ceresoli Date: Fri, 09 Jan 2026 08:31:41 +0100 Subject: [PATCH v2 10/12] drm/bridge: samsung-dsim: samsung_dsim_host_attach: use a temporary variable for the next bridge Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260109-drm-bridge-alloc-getput-drm_of_find_bridge-2-v2-10-8bad3ef90b9f@bootlin.com> References: <20260109-drm-bridge-alloc-getput-drm_of_find_bridge-2-v2-0-8bad3ef90b9f@bootlin.com> In-Reply-To: <20260109-drm-bridge-alloc-getput-drm_of_find_bridge-2-v2-0-8bad3ef90b9f@bootlin.com> To: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Philippe Cornu , benjamin.gaignard@linaro.org, Andrzej Hajda , Neil Armstrong , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Adrien Grassein , Liu Ying , Shawn Guo , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , Inki Dae , Jagan Teki , Marek Szyprowski Cc: Hui Pu , Thomas Petazzoni , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org, Luca Ceresoli X-Mailer: b4 0.14.3 X-Last-TLS-Session-Version: TLSv1.3 In preparation to handle refcounting of the out_bridge, we need to ensure the out_bridge pointer contains either a valid bridge pointer or NULL, not an ERR_PTR. Otherwise calls such as drm_bridge_get/put() would try to redeference an ERR_PTR. As a preliminary cleanup, add a temporary local 'next_bridge' pointer and only copy it in dsi->out_bridge as late as possible, i.e. just before calling pdata->host_ops->attach() which uses it (only in the exynos driver). Not strictly needed, but for symmetry move the clearing of dsi->out_bridge in samsung_dsim_host_detach() to after pdata->host_ops->detach(). Signed-off-by: Luca Ceresoli Acked-by: Maxime Ripard Tested-by: Marek Szyprowski --- Changes in v2: - fix "pointer set too late" bug (NULL pointer deref in the exynos case) - *not* add Acked-by: Maxime as the patch has changed --- drivers/gpu/drm/bridge/samsung-dsim.c | 26 +++++++++++++++++--------- 1 file changed, 17 insertions(+), 9 deletions(-) diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge= /samsung-dsim.c index eabc4c32f6ab..8dd058124e93 100644 --- a/drivers/gpu/drm/bridge/samsung-dsim.c +++ b/drivers/gpu/drm/bridge/samsung-dsim.c @@ -1886,6 +1886,7 @@ static int samsung_dsim_host_attach(struct mipi_dsi_h= ost *host, { struct samsung_dsim *dsi =3D host_to_dsi(host); const struct samsung_dsim_plat_data *pdata =3D dsi->plat_data; + struct drm_bridge *next_bridge; struct device *dev =3D dsi->dev; struct device_node *np =3D dev->of_node; struct device_node *remote; @@ -1924,17 +1925,17 @@ static int samsung_dsim_host_attach(struct mipi_dsi= _host *host, =20 panel =3D of_drm_find_panel(remote); if (!IS_ERR(panel)) { - dsi->out_bridge =3D devm_drm_panel_bridge_add(dev, panel); + next_bridge =3D devm_drm_panel_bridge_add(dev, panel); } else { - dsi->out_bridge =3D of_drm_find_bridge(remote); - if (!dsi->out_bridge) - dsi->out_bridge =3D ERR_PTR(-EINVAL); + next_bridge =3D of_drm_find_bridge(remote); + if (!next_bridge) + next_bridge =3D ERR_PTR(-EINVAL); } =20 of_node_put(remote); =20 - if (IS_ERR(dsi->out_bridge)) { - ret =3D PTR_ERR(dsi->out_bridge); + if (IS_ERR(next_bridge)) { + ret =3D PTR_ERR(next_bridge); DRM_DEV_ERROR(dev, "failed to find the bridge: %d\n", ret); return ret; } @@ -1958,10 +1959,13 @@ static int samsung_dsim_host_attach(struct mipi_dsi= _host *host, return ret; } =20 + // The next bridge can be used by host_ops->attach + dsi->out_bridge =3D next_bridge; + if (pdata->host_ops && pdata->host_ops->attach) { ret =3D pdata->host_ops->attach(dsi, device); if (ret) - return ret; + goto err_release_next_bridge; } =20 dsi->lanes =3D device->lanes; @@ -1969,6 +1973,10 @@ static int samsung_dsim_host_attach(struct mipi_dsi_= host *host, dsi->mode_flags =3D device->mode_flags; =20 return 0; + +err_release_next_bridge: + dsi->out_bridge =3D NULL; + return ret; } =20 static void samsung_dsim_unregister_te_irq(struct samsung_dsim *dsi) @@ -1985,11 +1993,11 @@ static int samsung_dsim_host_detach(struct mipi_dsi= _host *host, struct samsung_dsim *dsi =3D host_to_dsi(host); const struct samsung_dsim_plat_data *pdata =3D dsi->plat_data; =20 - dsi->out_bridge =3D NULL; - if (pdata->host_ops && pdata->host_ops->detach) pdata->host_ops->detach(dsi, device); =20 + dsi->out_bridge =3D NULL; + samsung_dsim_unregister_te_irq(dsi); =20 drm_bridge_remove(&dsi->bridge); --=20 2.52.0