From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay4-d.mail.gandi.net (relay4-d.mail.gandi.net [217.70.183.196]) (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 6FA8D202C50 for ; Mon, 16 Dec 2024 16:41:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.70.183.196 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734367276; cv=none; b=NQR9PocSG4X/HknBYG81wg996RVuNWklwf2dKRKiiEuPjmdanbbOEOf5q0hwD4Mve4E7F0178/q2GU+Xx+Od+0Y+8tlD6f3KoKFlSO8uqMWg5ImO9xuYwq+468p4VmvSu/xMRZbpvqf7W0sWi8XYSbX2m9sRojnyT2JIU9Hbqfs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734367276; c=relaxed/simple; bh=H0MySrUxWDCqvEAcb0pedeQRSOE3Bds2iksJxEoUuwM=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=K9p7gk9mYvSrFQQR88WbRGPDDj3haw3dhJnwxRErp9bhv/trcIhMf9Y4fHlAoiB7XGQ3u2U7mucQVbdd11HOMpzwFdh3coF+6kxFclyFhuWrtIErY5POq120qNrTYZaC55A7D/4IiiKZgCGFtx0o7BbdLwL1NmUvnER9b3A6lw8= 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=eyDGFgHV; arc=none smtp.client-ip=217.70.183.196 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="eyDGFgHV" Received: by mail.gandi.net (Postfix) with ESMTPSA id DC324E000F; Mon, 16 Dec 2024 16:41:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1734367272; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=qW3wdr4EeYIZ0MLaRPPuH3cK65j246cHF8/ZPxNc2Bo=; b=eyDGFgHVeEDhExDDMXCSOSgsB8v/VSm2hPy3ubebFzBaHgkY9OCIVc9nnBg43U2bRdhdvW ss9r9o+GQbM6f1QKp6acKn032ygY1oWgbk519MEvab2avDyHYqC3LlfOiM2ClxaZiUdHXf tZhTbUkPSbyf80lmr4Jd9HImCi3J6kdtpv/tEfVEOHd1mCFH/9Hcu3K3axOY2bSceJ9ujy OBFut0yli1R9jA6DDRwLg76sQpgCE7fPL7Zclp3m83/ZQcvhntvDhXmrVxrsA7gkqD/B+Z jGkIKakyPXSRc80NEp8IcCix2arnsXdmcdn0p3jEPCRkGE9aJxtSdb6X+KkTjA== From: Luca Ceresoli Date: Mon, 16 Dec 2024 17:40:51 +0100 Subject: [PATCH RESEND v3 4/4] drm/connector: warn when cleaning up a refcounted connector 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: 7bit Message-Id: <20241216-drm-small-improvements-v3-4-78bbc95ac776@bootlin.com> References: <20241216-drm-small-improvements-v3-0-78bbc95ac776@bootlin.com> In-Reply-To: <20241216-drm-small-improvements-v3-0-78bbc95ac776@bootlin.com> To: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter Cc: Dmitry Baryshkov , Jani Nikula , Thomas Petazzoni , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Luca Ceresoli , Louis Chauvet X-Mailer: b4 0.14.2 X-GND-Sasl: luca.ceresoli@bootlin.com Calling drm_connector_cleanup() should only be done via the free_cb => .destroy path, which cleans up the struct drm_connector only when the refcount drops to zero. A cleanup done with a refcount higher than 0 can result from buggy code, e.g. by doing cleanup directly in the drivers teardown code. Serious trouble can happen if this happens, so warn about it. Reviewed-by: Dmitry Baryshkov Signed-off-by: Luca Ceresoli --- drivers/gpu/drm/drm_connector.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c index fc35f47e2849ed6786d6223ac9c69e1c359fc648..e0bf9c490af43055de4caaee1580a4befbd608c5 100644 --- a/drivers/gpu/drm/drm_connector.c +++ b/drivers/gpu/drm/drm_connector.c @@ -624,6 +624,12 @@ void drm_connector_cleanup(struct drm_connector *connector) struct drm_device *dev = connector->dev; struct drm_display_mode *mode, *t; + /* + * Cleanup must happen when the last ref is put, via the + * drm_connector_free() callback. + */ + WARN_ON(drm_mode_object_read_refcount(&connector->base) != 0); + /* The connector should have been removed from userspace long before * it is finally destroyed. */ -- 2.34.1