From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933865AbbIDNlv (ORCPT ); Fri, 4 Sep 2015 09:41:51 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:50098 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932903AbbIDNJm (ORCPT ); Fri, 4 Sep 2015 09:09:42 -0400 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Dave Airlie , Jan Beulich , Jiri Slaby , Luis Henriques Subject: [PATCH 3.16.y-ckt 063/130] drm/radeon: fix hotplug race at startup Date: Fri, 4 Sep 2015 14:07:31 +0100 Message-Id: <1441372118-5933-64-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1441372118-5933-1-git-send-email-luis.henriques@canonical.com> References: <1441372118-5933-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.16 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.7-ckt17 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Dave Airlie commit 7f98ca454ad373fc1b76be804fa7138ff68c1d27 upstream. We apparantly get a hotplug irq before we've initialised modesetting, [drm] Loading R100 Microcode BUG: unable to handle kernel NULL pointer dereference at (null) IP: [] __mutex_lock_slowpath+0x23/0x91 *pde = 00000000 Oops: 0002 [#1] Modules linked in: radeon(+) drm_kms_helper ttm drm i2c_algo_bit backlight pcspkr psmouse evdev sr_mod input_leds led_class cdrom sg parport_pc parport floppy intel_agp intel_gtt lpc_ich acpi_cpufreq processor button mfd_core agpgart uhci_hcd ehci_hcd rng_core snd_intel8x0 snd_ac97_codec ac97_bus snd_pcm usbcore usb_common i2c_i801 i2c_core snd_timer snd soundcore thermal_sys CPU: 0 PID: 15 Comm: kworker/0:1 Not tainted 4.2.0-rc7-00015-gbf67402 #111 Hardware name: MicroLink /D850MV , BIOS MV85010A.86A.0067.P24.0304081124 04/08/2003 Workqueue: events radeon_hotplug_work_func [radeon] task: f6ca5900 ti: f6d3e000 task.ti: f6d3e000 EIP: 0060:[] EFLAGS: 00010282 CPU: 0 EIP is at __mutex_lock_slowpath+0x23/0x91 EAX: 00000000 EBX: f5e900fc ECX: 00000000 EDX: fffffffe ESI: f6ca5900 EDI: f5e90100 EBP: f5e90000 ESP: f6d3ff0c DS: 007b ES: 007b FS: 0000 GS: 0000 SS: 0068 CR0: 8005003b CR2: 00000000 CR3: 36f61000 CR4: 000006d0 Stack: f5e90100 00000000 c103c4c1 f6d2a5a0 f5e900fc f6df394c c125f162 f8b0faca f6d2a5a0 c138ca00 f6df394c f7395600 c1034741 00d40000 00000000 f6d2a5a0 c138ca00 f6d2a5b8 c138ca10 c1034b58 00000001 f6d40000 f6ca5900 f6d0c940 Call Trace: [] ? dequeue_task_fair+0xa4/0xb7 [] ? mutex_lock+0x9/0xa [] ? radeon_hotplug_work_func+0x17/0x57 [radeon] [] ? process_one_work+0xfc/0x194 [] ? worker_thread+0x18d/0x218 [] ? rescuer_thread+0x1d5/0x1d5 [] ? kthread+0x7b/0x80 [] ? ret_from_kernel_thread+0x20/0x30 [] ? init_completion+0x18/0x18 Code: 42 08 e8 8e a6 dd ff c3 57 56 53 83 ec 0c 8b 35 48 f7 37 c1 8b 10 4a 74 1a 89 c3 8d 78 04 8b 40 08 89 63 Reported-and-Tested-by: Meelis Roos Signed-off-by: Dave Airlie Cc: Jan Beulich Cc: Jiri Slaby Signed-off-by: Luis Henriques --- drivers/gpu/drm/radeon/radeon_irq_kms.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/gpu/drm/radeon/radeon_irq_kms.c b/drivers/gpu/drm/radeon/radeon_irq_kms.c index dd49f8c61878..4ae8c2c49d52 100644 --- a/drivers/gpu/drm/radeon/radeon_irq_kms.c +++ b/drivers/gpu/drm/radeon/radeon_irq_kms.c @@ -79,6 +79,11 @@ static void radeon_hotplug_work_func(struct work_struct *work) struct drm_mode_config *mode_config = &dev->mode_config; struct drm_connector *connector; + /* we can race here at startup, some boards seem to trigger + * hotplug irqs when they shouldn't. */ + if (!rdev->mode_info.mode_config_initialized) + return; + mutex_lock(&mode_config->mutex); if (mode_config->num_connector) { list_for_each_entry(connector, &mode_config->connector_list, head)