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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5FA66C433F5 for ; Sat, 1 Oct 2022 01:23:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233238AbiJABXS (ORCPT ); Fri, 30 Sep 2022 21:23:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37700 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229952AbiJABWR (ORCPT ); Fri, 30 Sep 2022 21:22:17 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C26A71110 for ; Fri, 30 Sep 2022 18:19:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1664587173; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=IDL/AgTFWdm+PP/N7/EovNn2CFq5LCV9poLaDqClvoQ=; b=FVkx7Pr4QJZre7vkhoYsIU3kCsNK+ONERx9BkHuVS4zEuGZpIZlWeTArHC2KfnVF7AyvQu ZO8ZmD+fMOc2u8TTwkQr4YJJozxmx2gi0kVZ03cNaS4xKl5PtUK52qk4CmvDYFPGzCBuyI b+wuj1vR9wLaraCcqwzRkIlNiVhph8E= Received: from mail-ed1-f71.google.com (mail-ed1-f71.google.com [209.85.208.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-369-fDxz7-gXP0yITLD4Fy3f0Q-1; Fri, 30 Sep 2022 21:19:32 -0400 X-MC-Unique: fDxz7-gXP0yITLD4Fy3f0Q-1 Received: by mail-ed1-f71.google.com with SMTP id y14-20020a056402440e00b0044301c7ccd9so4618970eda.19 for ; Fri, 30 Sep 2022 18:19:31 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date; bh=IDL/AgTFWdm+PP/N7/EovNn2CFq5LCV9poLaDqClvoQ=; b=cQcqSviRv2mj85wbQKQ0np5OPACL2zu0ERnik03oCDpKhT3TNkDLTrp6PWeh0Iyxjb S10H+ZRadeRg+DkT9IqfRzhcZG3vL52UcSv6oxphXmrcFNK+2+jlY0HsJ6EfmHk+Zaxa F7eS7idUnTrg7kerP1jyU1QbgRmlktvRG+ucBHI4p2uF7fzU4ziZ/sfHP+QyFv8iWmXS m94rwM9sFO77bknEcsjF353CTxWsDn7mAzxW26FDy1fYSJ3K/aAV+oDUw88+VHWD7PFC DzeflDQpHHmotZt40UG/2p3fkAGOJH1O+CvUu14sQYTTqoftXlknsYpYJAJWReZGE35C KrtA== X-Gm-Message-State: ACrzQf27v4SIMnNJ6ONSLSrMDdyfa5RC1v6JtE8YWz29Q8ltxQ73sA73 t1qp0r43k3Wkoc52LP93/Za2A+jPTDAT4Ev4S90tgOsvL+rcXlbuwiDtKOYdqpecP4JinJRXsKC SuE8BtU5jJz/Chv7n/qGcUhxr X-Received: by 2002:a17:907:7f13:b0:783:6227:b939 with SMTP id qf19-20020a1709077f1300b007836227b939mr7826775ejc.416.1664587171148; Fri, 30 Sep 2022 18:19:31 -0700 (PDT) X-Google-Smtp-Source: AMsMyM7wyZtxUwtQbZgS2YO5wic9h7BmWOQ9xCf4l19faoKnOUNoHKq43TyHpezKHLZZwq7kSKONgA== X-Received: by 2002:a17:907:7f13:b0:783:6227:b939 with SMTP id qf19-20020a1709077f1300b007836227b939mr7826762ejc.416.1664587170962; Fri, 30 Sep 2022 18:19:30 -0700 (PDT) Received: from pollux.redhat.com ([2a02:810d:4b40:2ee8:642:1aff:fe31:a15c]) by smtp.gmail.com with ESMTPSA id oz23-20020a170906cd1700b007724b8e6576sm1931950ejb.32.2022.09.30.18.19.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 30 Sep 2022 18:19:30 -0700 (PDT) From: Danilo Krummrich To: daniel@ffwll.ch, airlied@linux.ie, tzimmermann@suse.de, mripard@kernel.org, liviu.dudau@arm.com, brian.starkey@arm.com Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Danilo Krummrich Subject: [PATCH drm-misc-next v3 6/7] drm/arm/hdlcd: debugfs: protect device resources after removal Date: Sat, 1 Oct 2022 03:19:04 +0200 Message-Id: <20221001011905.433408-7-dakr@redhat.com> X-Mailer: git-send-email 2.37.3 In-Reply-To: <20221001011905.433408-1-dakr@redhat.com> References: <20221001011905.433408-1-dakr@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org (Hardware) resources which are bound to the driver and device lifecycle must not be accessed after the device and driver are unbound. However, the DRM device isn't freed as long as the last user didn't close it, hence userspace can still call into the driver. Therefore protect the critical sections which are accessing those resources with drm_dev_enter() and drm_dev_exit(). Signed-off-by: Danilo Krummrich --- drivers/gpu/drm/arm/hdlcd_drv.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/arm/hdlcd_drv.c b/drivers/gpu/drm/arm/hdlcd_drv.c index e41def6d47cc..020c7d0c70a5 100644 --- a/drivers/gpu/drm/arm/hdlcd_drv.c +++ b/drivers/gpu/drm/arm/hdlcd_drv.c @@ -204,11 +204,19 @@ static int hdlcd_show_pxlclock(struct seq_file *m, void *arg) struct drm_info_node *node = (struct drm_info_node *)m->private; struct drm_device *drm = node->minor->dev; struct hdlcd_drm_private *hdlcd = drm_to_hdlcd_priv(drm); - unsigned long clkrate = clk_get_rate(hdlcd->clk); - unsigned long mode_clock = hdlcd->crtc.mode.crtc_clock * 1000; + unsigned long clkrate, mode_clock; + int idx; + + if (!drm_dev_enter(drm, &idx)) + return -ENODEV; + + clkrate = clk_get_rate(hdlcd->clk); + mode_clock = hdlcd->crtc.mode.crtc_clock * 1000; seq_printf(m, "hw : %lu\n", clkrate); seq_printf(m, "mode: %lu\n", mode_clock); + + drm_dev_exit(idx); return 0; } -- 2.37.3