From nobody Fri Apr 10 20:26:24 2026 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 BDF56C28D13 for ; Fri, 19 Aug 2022 23:11:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243812AbiHSXLh (ORCPT ); Fri, 19 Aug 2022 19:11:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35328 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243682AbiHSXL1 (ORCPT ); Fri, 19 Aug 2022 19:11:27 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 23ECAD5DEB for ; Fri, 19 Aug 2022 16:11:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1660950680; 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=0y/a4pTSF6VtadOpwMNTC/mvZDJbVIcTrD8TXNTMH9w=; b=e4sUl5rhbcDtgpuKtwGdwId8WiJHqNZEe3aWFrcnsBqI5QvP9XKWtSyUijHVnUfQwvA3ON NlmAKv1+ynauy/ZXxp86DYWTGQYtbEkvu9pOvGVGGVNeTEmS9wTLtKdEOqBa8JuuJhvbwr ohKkn4vW+A8RJgwcBcob4xWHZu5bucQ= Received: from mail-ej1-f72.google.com (mail-ej1-f72.google.com [209.85.218.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-360-b6xnA5ofMZWPN1goblxMEA-1; Fri, 19 Aug 2022 19:11:19 -0400 X-MC-Unique: b6xnA5ofMZWPN1goblxMEA-1 Received: by mail-ej1-f72.google.com with SMTP id hv19-20020a17090760d300b00730d0a018a6so1982635ejc.21 for ; Fri, 19 Aug 2022 16:11:19 -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; bh=0y/a4pTSF6VtadOpwMNTC/mvZDJbVIcTrD8TXNTMH9w=; b=4sLZhWBZ3dHhNZ3dCNaj907eD5UXWu04unHC8ZvkB/uZQMjyWPKY/e34LJX9YsyjMe o+FCL8lpb3tDPktMzYsap+28NW9apMmpxXkebf2s7WBYX+De1BTf2eMDR9FjJsfOsTXV n3oiLxSVLfiId5UxtXYHBbntJHEoN4ZgzyqKFpu0kyPidcftpjD03D41w6YIv/HrhwEN nKBoQwAeU4PndcExlyGDFJl1oMNgKuyJEq+1MrKKgZlhgss9V00q0BeYOV/UVKQgV9J4 saogB4ARARaezGWe19mCKnsT1bbsAheNQ1SSIoavok3gTYlehgZVJInWHp/1Fx9drxVt O0EQ== X-Gm-Message-State: ACgBeo13EA+YA9wz5DoH+MIjfm+dukRrzWpkdEscnJdGWbe8b6KdlhKN Jph52beYHYFvwgMxTFW7yipX7EgD3OvIzfGHzw2XRWyh+IDpvGePJIc5HdkbbZKv6LQPCqUNAgW dFdxumTCG8wKX1+HszKDw51Rd X-Received: by 2002:a05:6402:2714:b0:43d:ca4f:d2a2 with SMTP id y20-20020a056402271400b0043dca4fd2a2mr7764355edd.185.1660950678519; Fri, 19 Aug 2022 16:11:18 -0700 (PDT) X-Google-Smtp-Source: AA6agR5t8ZWTVk4y4Y4BTXVKS9pOWxmu4s8KtL9YowyUh5bjRrc9ssHwXdvbPAqefLHaOgjt3XLApA== X-Received: by 2002:a05:6402:2714:b0:43d:ca4f:d2a2 with SMTP id y20-20020a056402271400b0043dca4fd2a2mr7764349edd.185.1660950678398; Fri, 19 Aug 2022 16:11:18 -0700 (PDT) Received: from pollux.redhat.com ([2a02:810d:4b40:2ee8:642:1aff:fe31:a15c]) by smtp.gmail.com with ESMTPSA id d5-20020a17090694c500b00734bfab4d59sm2923078ejy.170.2022.08.19.16.11.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 19 Aug 2022 16:11:18 -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 7/7] drm/arm/hdlcd: debugfs: protect device resources after removal Date: Sat, 20 Aug 2022 01:10:58 +0200 Message-Id: <20220819231058.647658-8-dakr@redhat.com> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220819231058.647658-1-dakr@redhat.com> References: <20220819231058.647658-1-dakr@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" (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_dr= v.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, vo= id *arg) struct drm_info_node *node =3D (struct drm_info_node *)m->private; struct drm_device *drm =3D node->minor->dev; struct hdlcd_drm_private *hdlcd =3D drm_to_hdlcd_priv(drm); - unsigned long clkrate =3D clk_get_rate(hdlcd->clk); - unsigned long mode_clock =3D hdlcd->crtc.mode.crtc_clock * 1000; + unsigned long clkrate, mode_clock; + int idx; + + if (!drm_dev_enter(drm, &idx)) + return -ENODEV; + + clkrate =3D clk_get_rate(hdlcd->clk); + mode_clock =3D hdlcd->crtc.mode.crtc_clock * 1000; =20 seq_printf(m, "hw : %lu\n", clkrate); seq_printf(m, "mode: %lu\n", mode_clock); + + drm_dev_exit(idx); return 0; } =20 --=20 2.37.2