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 3E9A8C369BD for ; Wed, 16 Apr 2025 12:31:19 +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: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=NOxGjbnSJKJEcLAzyE6sh3fRZZh2VBbNd+6z/m20T1w=; b=kV6rLQYeS+SLFybTMnRweEdI64 ZV5bnuDXRaoPVhbyE9GyR1jQrHbVWtPnkW8tya1SnOkRtjYl6YCjVPTlpKZSCnLEz3NO81USVb1uQ w3jpM9c7ONxe8Iueslmf3PPLC7Tq9P3QRHQ6ljZYEY+C8HjtnWzrFAKDHqo8HbXvRHmFO5wIph2YV fYogq1YM+LUA8+5NkKGgqnxXqL7Vy5P92zf/ch0DzZEogO2njYmIiYdEAAVjSHvmKtZcqhfzffJaI X8Z3xP/waw4D6d4+XSPbOYhQug6L80HGN3P25xceDOnpkuQ6l+qGSUZiTO80GYz4hyaksmgp5CZUL Dw2581Qg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1u51v1-00000009WJm-2XqE; Wed, 16 Apr 2025 12:31:07 +0000 Received: from perceval.ideasonboard.com ([213.167.242.64]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1u51qT-00000009VOZ-2EV6; Wed, 16 Apr 2025 12:26:27 +0000 Received: from [192.168.88.20] (91-158-153-178.elisa-laajakaista.fi [91.158.153.178]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 18B80446; Wed, 16 Apr 2025 14:24:17 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1744806259; bh=zZyoUoQs57ugcr6pi7AFEtiMgwqRDtvhMHoc4UZWdWY=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=JAF4hkeCioakqnxQz9bTUPttghD/RANLFweNIr16lzd8pBObABa768eAO0Ei9TL72 7cO7bfN79c4QAdYcmgkJgHS8kooHXkT81GJvZaMYZgJWIFvPnZjQhsTBa/3cZFLcSN tTqDr7CfXSzOZtaSh9msG9GiqvphRDXZnigsfMjA= Message-ID: Date: Wed, 16 Apr 2025 15:26:17 +0300 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 29/34] drm: zynqmp_dp: convert to devm_drm_bridge_alloc() API To: Luca Ceresoli Cc: Anusha Srivatsa , Paul Kocialkowski , Dmitry Baryshkov , =?UTF-8?Q?Herv=C3=A9_Codina?= , Hui Pu , Thomas Petazzoni , dri-devel@lists.freedesktop.org, asahi@lists.linux.dev, linux-kernel@vger.kernel.org, chrome-platform@lists.linux.dev, imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, linux-amlogic@lists.infradead.org, linux-renesas-soc@vger.kernel.org, platform-driver-x86@vger.kernel.org, linux-samsung-soc@vger.kernel.org, linux-arm-msm@vger.kernel.org, freedreno@lists.freedesktop.org, linux-stm32@st-md-mailman.stormreply.com, Michal Simek , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Andrzej Hajda , Neil Armstrong , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Jagan Teki , Shawn Guo , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , Douglas Anderson , Chun-Kuang Hu , Krzysztof Kozlowski , Dmitry Baryshkov , "Sagar, Vishal" References: <20250407-drm-bridge-convert-to-alloc-api-v1-0-42113ff8d9c0@bootlin.com> <20250407-drm-bridge-convert-to-alloc-api-v1-29-42113ff8d9c0@bootlin.com> Content-Language: en-US From: Tomi Valkeinen Autocrypt: addr=tomi.valkeinen@ideasonboard.com; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250416_052626_036681_2D8E103C X-CRM114-Status: GOOD ( 20.04 ) 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 Hi, On 07/04/2025 17:23, Luca Ceresoli wrote: > This is the new API for allocating DRM bridges. > > This driver has a peculiar structure. zynqmp_dpsub.c is the actual driver, > which delegates to a submodule (zynqmp_dp.c) the allocation of a > sub-structure embedding the drm_bridge and its initialization, however it > does not delegate the drm_bridge_add(). Hence, following carefully the code > flow, it is correct to change the allocation function and .funcs assignment > in the submodule, while the drm_bridge_add() is not in that submodule. > > Signed-off-by: Luca Ceresoli > > --- > > Cc: Laurent Pinchart > Cc: Michal Simek > Cc: Tomi Valkeinen > --- > drivers/gpu/drm/xlnx/zynqmp_dp.c | 7 +++---- > 1 file changed, 3 insertions(+), 4 deletions(-) > > diff --git a/drivers/gpu/drm/xlnx/zynqmp_dp.c b/drivers/gpu/drm/xlnx/zynqmp_dp.c > index 11d2415fb5a1f7fad03421898331289f2295d68b..de22b6457a78a7a2110f9f308d0b5a8700544010 100644 > --- a/drivers/gpu/drm/xlnx/zynqmp_dp.c > +++ b/drivers/gpu/drm/xlnx/zynqmp_dp.c > @@ -2439,9 +2439,9 @@ int zynqmp_dp_probe(struct zynqmp_dpsub *dpsub) > struct zynqmp_dp *dp; > int ret; > > - dp = kzalloc(sizeof(*dp), GFP_KERNEL); > - if (!dp) > - return -ENOMEM; > + dp = devm_drm_bridge_alloc(&pdev->dev, struct zynqmp_dp, bridge, &zynqmp_dp_bridge_funcs); > + if (IS_ERR(dp)) > + return PTR_ERR(dp); > > dp->dev = &pdev->dev; > dp->dpsub = dpsub; > @@ -2488,7 +2488,6 @@ int zynqmp_dp_probe(struct zynqmp_dpsub *dpsub) > > /* Initialize the bridge. */ > bridge = &dp->bridge; > - bridge->funcs = &zynqmp_dp_bridge_funcs; > bridge->ops = DRM_BRIDGE_OP_DETECT | DRM_BRIDGE_OP_EDID > | DRM_BRIDGE_OP_HPD; > bridge->type = DRM_MODE_CONNECTOR_DisplayPort; > I haven't had time to look at this more, but jfyi: I got this when unloading modules, but it doesn't seem to happen every time: [ 103.010533] ------------[ cut here ]------------ [ 103.015415] refcount_t: underflow; use-after-free. [ 103.020657] WARNING: CPU: 2 PID: 392 at lib/refcount.c:28 refcount_warn_saturate+0xf4/0x148 [ 103.029056] Modules linked in: zynqmp_dpsub(-) display_connector drm_display_helper drm_dma_helper drm_kms_helper drm drm_p anel_orientation_quirks [ 103.042437] CPU: 2 UID: 0 PID: 392 Comm: rmmod Not tainted 6.15.0-rc2+ #3 PREEMPT [ 103.050035] Hardware name: ZynqMP ZCU106 RevA (DT) [ 103.054836] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 103.061814] pc : refcount_warn_saturate+0xf4/0x148 [ 103.066632] lr : refcount_warn_saturate+0xf4/0x148 [ 103.071441] sp : ffff800083b5bbb0 [ 103.074766] x29: ffff800083b5bbb0 x28: ffff000806b23780 x27: 0000000000000000 [ 103.081953] x26: 0000000000000000 x25: 0000000000000000 x24: ffff000801a68400 [ 103.089141] x23: ffff800081311a20 x22: ffff800083b5bc38 x21: ffff000801a68010 [ 103.096329] x20: ffff0008040676c0 x19: ffff000804067240 x18: 0000000000000006 [ 103.103517] x17: 2e30303030303464 x16: 662d7968703a7968 x15: ffff800083b5b5a0 [ 103.110705] x14: 0000000000000000 x13: 00000000000c0000 x12: 0000000000000000 [ 103.117892] x11: ffff80008163d6bc x10: 0000000000000028 x9 : ffff800080ead38c [ 103.125080] x8 : ffff800083b5b908 x7 : 0000000000000000 x6 : ffff800083b5b9c0 [ 103.132268] x5 : ffff800083b5b948 x4 : 0000000000000001 x3 : 00000000000000db [ 103.139455] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff000806b23780 [ 103.146644] Call trace: [ 103.149102] refcount_warn_saturate+0xf4/0x148 (P) [ 103.153918] drm_bridge_put.part.0+0x88/0xa0 [drm] [ 103.159188] drm_bridge_put_void+0x1c/0x38 [drm] [ 103.164231] devm_action_release+0x1c/0x30 [ 103.168354] release_nodes+0x68/0xa8 [ 103.171957] devres_release_all+0x98/0xf0 [ 103.175993] device_unbind_cleanup+0x20/0x70 [ 103.180291] device_release_driver_internal+0x208/0x250 [ 103.185542] driver_detach+0x54/0xa8 [ 103.189145] bus_remove_driver+0x78/0x108 [ 103.193181] driver_unregister+0x38/0x70 [ 103.197131] platform_driver_unregister+0x1c/0x30 [ 103.201862] zynqmp_dpsub_driver_exit+0x18/0x1100 [zynqmp_dpsub] [ 103.207931] __arm64_sys_delete_module+0x1a8/0x2d0 [ 103.212748] invoke_syscall+0x50/0x120 [ 103.216524] el0_svc_common.constprop.0+0x48/0xf0 [ 103.221256] do_el0_svc+0x24/0x38 [ 103.224598] el0_svc+0x48/0x128 [ 103.227766] el0t_64_sync_handler+0x10c/0x138 [ 103.232150] el0t_64_sync+0x1a4/0x1a8 [ 103.235841] irq event stamp: 7936 [ 103.239173] hardirqs last enabled at (7935): [] finish_task_switch.isra.0+0xb0/0x2a0 [ 103.248600] hardirqs last disabled at (7936): [] el1_dbg+0x24/0x90 [ 103.256369] softirqs last enabled at (7930): [] handle_softirqs+0x4a0/0x4c0 [ 103.265007] softirqs last disabled at (7905): [] __do_softirq+0x1c/0x28 [ 103.273211] ---[ end trace 0000000000000000 ]--- Tomi