From patchwork Mon Aug 23 17:14:31 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Desmond Cheong Zhi Xi X-Patchwork-Id: 501667 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EDE8BC4338F for ; Mon, 23 Aug 2021 17:15:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CFC5D613BD for ; Mon, 23 Aug 2021 17:15:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230506AbhHWRPt (ORCPT ); Mon, 23 Aug 2021 13:15:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40382 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229479AbhHWRPs (ORCPT ); Mon, 23 Aug 2021 13:15:48 -0400 Received: from mail-pl1-x62f.google.com (mail-pl1-x62f.google.com [IPv6:2607:f8b0:4864:20::62f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E9681C061575; Mon, 23 Aug 2021 10:15:05 -0700 (PDT) Received: by mail-pl1-x62f.google.com with SMTP id b9so6173768plx.2; Mon, 23 Aug 2021 10:15:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=fG8NNf17FBZn+wJbjBPwz4tCgByeKPl/oOGmuCamRZg=; b=qy03Myz+IJo3XI2Pa/OjLNRQVcFA9XwYXtgRK5gisKBMmbuz2yibe6UT9WHuswtyJR nNwK2qHCYX+NCPxlsqyWdt+9f3pUq9DGpeRNVwWglb/RtPk8TBtetgQ4PQiMQOdziAyX k8ISZXwFuRoGWI3eHgr/s4rC9gCy8J6At6eViigBk0XIJkuq8NHLNtb/rNGW0/yoaPqr xpD4LdeBUFkWPNHZOheFfYfpZhf4II00YbIC8ggdQnyPLVxlJFAtpbq0QUiB2erXeZmA sMQ5X0SmNBoDFWFtT2fdW+qt4Yplxd8KjsxPkvbdGJECBAklq+/e7Pm/b9pOY+HpCiEJ u3wg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=fG8NNf17FBZn+wJbjBPwz4tCgByeKPl/oOGmuCamRZg=; b=iVTnp635qc3K3TSarritb20kAmPQJoRbAReEJI+6jqPaAECWtVXjs+GeqxnWujPOR2 rm9pHGn2noy21HsaZDNWZW3Un1KDKunf4Xpu/pUCl/p45J13bhQtTsg+xvOdSYymvDJk enPVEQOJALEZB2b/k75hB41/dqbrstnDTGc3AHmXl2wVhMitGdXXmUcMxuoDN6GLwah6 jlUhZdOsNkb7RSmrnTdC81HDe2c/6jvdNWB6MFA0uSSeogEcNO1n+mXoIg+qkAN1dgOn AnHc6zqoDNkjMzqoeqxR9yd4W7nWrV7jiteWpHcNYswWk4xcLGxDOmw1XSKNC7fo//KS eI2g== X-Gm-Message-State: AOAM5328+b0YQ+bCNU6Bes8vfjH9QpraMafWNMuJEDa4U7cmCNIEJyZN 2aT/Rma8gm/PJR22eBi6IS4= X-Google-Smtp-Source: ABdhPJwaSxPqYlsApUTHXQKlyVHVNw2D+LT4RVtxvURlnrOCQd9tMJT/xzN3FNc9RODVpb5i7bDn5w== X-Received: by 2002:a17:90a:f285:: with SMTP id fs5mr2379999pjb.148.1629738905421; Mon, 23 Aug 2021 10:15:05 -0700 (PDT) Received: from localhost.localdomain ([118.200.190.93]) by smtp.gmail.com with ESMTPSA id q4sm14290830pjd.52.2021.08.23.10.15.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 23 Aug 2021 10:15:04 -0700 (PDT) From: Desmond Cheong Zhi Xi To: maarten.lankhorst@linux.intel.com, mripard@kernel.org, tzimmermann@suse.de, airlied@linux.ie, daniel@ffwll.ch, sumit.semwal@linaro.org, christian.koenig@amd.com Cc: Desmond Cheong Zhi Xi , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, intel-gfx@lists.freedesktop.org, linux-media@vger.kernel.org, linaro-mm-sig@lists.linaro.org, skhan@linuxfoundation.org, gregkh@linuxfoundation.org, linux-kernel-mentees@lists.linuxfoundation.org Subject: [PATCH v5 0/6] drm: update locking for modesetting Date: Tue, 24 Aug 2021 01:14:31 +0800 Message-Id: <20210823171437.829404-1-desmondcheongzx@gmail.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Hi, I updated the series to untangle more lock inversions caught by the Intel-gfx CI, but again there might be more that I missed. This series now converts drm_device.master_mutex into master_rwsem, and also removes drm_file.master_lookup_lock. Overall, this series makes the following changes: - Patch 1: Fix a potential null ptr dereference in drm_master_release - Patch 2: Convert master_mutex into rwsem (avoids creating a new lock) - Patch 3: Update global mutex locking in the ioctl handler (avoids deadlock when grabbing read lock on master_rwsem in drm_ioctl_kernel) - Patch 4: Plug races with drm modesetting rights - Patch 5: Untagle remaining lock hierarchy inversions between modeset_mutex and master_rwsem - Patch 6: Replace master_lookup_lock with master_rwsem v4 -> v5: - Avoid calling drm_file_get_master while holding on to the modeset mutex, caught by the Intel-gfx CI (split previous patch 5 into the new patch 5 & 6) v3 -> v4 (suggested by Daniel Vetter): - Drop a patch that added an unnecessary master_lookup_lock in drm_master_release (previously patch 2) - Drop a patch that addressed a non-existent race in drm_is_current_master_locked (previously patch 3) - Remove fixes for non-existent null ptr dereferences (previous patch 4) - Protect drm_master.magic_map,unique{_len} with master_rwsem instead of master_lookup_lock (dropped previous patch 5) - Drop the patch that moved master_lookup_lock into struct drm_device (previously patch 1) - Drop a patch to export task_work_add (previously patch 8) - Revert the check for the global mutex in the ioctl handler to use drm_core_check_feature instead of drm_dev_needs_global_mutex - Push down master_rwsem locking for selected ioctls to avoid lock hierarchy inversions, and to allow us to hold write locks on master_rwsem instead of flushing readers - Remove master_lookup_lock by replacing it with master_rwsem v2 -> v3: - Unexport drm_master_flush, as suggested by Daniel Vetter. - Merge master_mutex and master_rwsem, as suggested by Daniel Vetter. - Export task_work_add, reported by kernel test robot. - Make master_flush static, reported by kernel test robot. - Move master_lookup_lock into struct drm_device. - Add a missing lock on master_lookup_lock in drm_master_release. - Fix a potential race in drm_is_current_master_locked. - Fix potential null ptr dereferences in drm_{auth, ioctl}. - Protect magic_map,unique{_len} with master_lookup_lock. - Convert master_mutex into a rwsem. - Update global mutex locking in the ioctl handler. v1 -> v2 (suggested by Daniel Vetter): - Address an additional race when drm_open runs. - Switch from SRCU to rwsem to synchronise readers and writers. - Implement drm_master_flush with task_work so that flushes can be queued to run before returning to userspace without creating a new DRM_MASTER_FLUSH ioctl flag. Best wishes, Desmond Desmond Cheong Zhi Xi (6): drm: fix null ptr dereference in drm_master_release drm: convert drm_device.master_mutex into a rwsem drm: lock drm_global_mutex earlier in the ioctl handler drm: avoid races with modesetting rights drm: avoid circular locks with modeset_mutex and master_rwsem drm: remove drm_file.master_lookup_lock drivers/gpu/drm/drm_atomic_uapi.c | 4 +- drivers/gpu/drm/drm_auth.c | 57 +++++++++++---------- drivers/gpu/drm/drm_debugfs.c | 4 +- drivers/gpu/drm/drm_drv.c | 3 +- drivers/gpu/drm/drm_encoder.c | 7 ++- drivers/gpu/drm/drm_file.c | 7 ++- drivers/gpu/drm/drm_framebuffer.c | 2 +- drivers/gpu/drm/drm_internal.h | 1 + drivers/gpu/drm/drm_ioctl.c | 48 +++++++++++------- drivers/gpu/drm/drm_lease.c | 83 ++++++++++++++----------------- drivers/gpu/drm/drm_mode_object.c | 16 ++++-- drivers/gpu/drm/drm_plane.c | 17 +++++-- drivers/gpu/drm/drm_property.c | 6 +-- include/drm/drm_auth.h | 6 +-- include/drm/drm_device.h | 15 ++++-- include/drm/drm_file.h | 17 ++----- include/drm/drm_lease.h | 4 +- 17 files changed, 165 insertions(+), 132 deletions(-)