From patchwork Tue Oct 21 10:55:37 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Dheeraj Jamwal X-Patchwork-Id: 5120411 Return-Path: X-Original-To: patchwork-ltsi-dev@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 9A1C49F349 for ; Tue, 21 Oct 2014 11:55:16 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id CE3522013A for ; Tue, 21 Oct 2014 11:55:15 +0000 (UTC) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id F3D7220138 for ; Tue, 21 Oct 2014 11:55:14 +0000 (UTC) Received: from mail.linux-foundation.org (localhost [127.0.0.1]) by mail.linuxfoundation.org (Postfix) with ESMTP id 5A29C1287; Tue, 21 Oct 2014 11:11:23 +0000 (UTC) X-Original-To: ltsi-dev@lists.linuxfoundation.org Delivered-To: ltsi-dev@mail.linuxfoundation.org Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 1E9FBCB6 for ; Tue, 21 Oct 2014 11:11:22 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by smtp1.linuxfoundation.org (Postfix) with ESMTP id 9D5571FB50 for ; Tue, 21 Oct 2014 11:11:21 +0000 (UTC) Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga101.fm.intel.com with ESMTP; 21 Oct 2014 04:11:10 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.04,761,1406617200"; d="scan'208";a="617799161" Received: from ubuntu-desktop.png.intel.com ([10.221.122.25]) by fmsmga002.fm.intel.com with ESMTP; 21 Oct 2014 04:11:09 -0700 From: Dheeraj Jamwal To: ltsi-dev@lists.linuxfoundation.org Date: Tue, 21 Oct 2014 18:55:37 +0800 Message-Id: <1413889294-31328-738-git-send-email-dheerajx.s.jamwal@intel.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1413889294-31328-1-git-send-email-dheerajx.s.jamwal@intel.com> References: <1413889294-31328-1-git-send-email-dheerajx.s.jamwal@intel.com> MIME-Version: 1.0 X-Spam-Status: No, score=-5.6 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org Subject: [LTSI-dev] [PATCH 0737/1094] drm/i915: Fix deadlock during driver init on ILK X-BeenThere: ltsi-dev@lists.linuxfoundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: "A list to discuss patches, development, and other things related to the LTSI project" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: ltsi-dev-bounces@lists.linuxfoundation.org Errors-To: ltsi-dev-bounces@lists.linuxfoundation.org X-Virus-Scanned: ClamAV using ClamSMTP From: Ville Syrjälä We have a struct_mutex deadlock during driver init on ILK [ 54.320273] ============================================= [ 54.320371] [ INFO: possible recursive locking detected ] [ 54.320471] 3.15.0-rc2-flip_race+ #2 Not tainted [ 54.320567] --------------------------------------------- [ 54.320665] modprobe/2178 is trying to acquire lock: [ 54.320762] (&dev->struct_mutex){+.+.+.}, at: [] intel_enable_gt_powersave+0xa5/0x9d0 [i915] [ 54.321111] [ 54.321111] but task is already holding lock: [ 54.321250] (&dev->struct_mutex){+.+.+.}, at: [] intel_modeset_init_hw+0x3e/0x60 [i915] [ 54.321583] [ 54.321583] other info that might help us debug this: [ 54.321724] Possible unsafe locking scenario: [ 54.321724] [ 54.321863] CPU0 [ 54.321954] ---- [ 54.322046] lock(&dev->struct_mutex); [ 54.322221] lock(&dev->struct_mutex); [ 54.322397] [ 54.322397] *** DEADLOCK *** [ 54.322397] [ 54.322638] May be due to missing lock nesting notation [ 54.322638] [ 54.322781] 4 locks held by modprobe/2178: [ 54.322875] #0: (&dev->mutex){......}, at: [] __driver_attach+0x5b/0xb0 [ 54.323230] #1: (&dev->mutex){......}, at: [] __driver_attach+0x69/0xb0 [ 54.323582] #2: (drm_global_mutex){+.+.+.}, at: [] drm_dev_register+0x2d/0x120 [drm] [ 54.323945] #3: (&dev->struct_mutex){+.+.+.}, at: [] intel_modeset_init_hw+0x3e/0x60 [i915] This regression got introduced in: commit 586d5270b60dc1f35cc3ca982d403765bad77965 Author: Imre Deak Date: Mon Apr 14 20:24:28 2014 +0300 drm/i915: move getting struct_mutex lower in the callstack during GPU reset Fix the problem by not taking struct_mutex around intel_enable_gt_powersave() in intel_modeset_init_hw() since intel_enable_gt_powersave() now grabs the mutex itself. Signed-off-by: Ville Syrjälä Signed-off-by: Daniel Vetter (cherry picked from commit 8a6543ba4719ff940b22ce9f9830a9c3fd9e1b60) Signed-off-by: Dheeraj Jamwal --- drivers/gpu/drm/i915/intel_display.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index df7de85..8652ea1 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -11245,9 +11245,7 @@ void intel_modeset_init_hw(struct drm_device *dev) intel_reset_dpio(dev); - mutex_lock(&dev->struct_mutex); intel_enable_gt_powersave(dev); - mutex_unlock(&dev->struct_mutex); } void intel_modeset_suspend_hw(struct drm_device *dev)