From patchwork Wed Nov 14 22:23:05 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sasha Levin X-Patchwork-Id: 10683167 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 3AD9214DB for ; Wed, 14 Nov 2018 22:24:36 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2C7102AEA2 for ; Wed, 14 Nov 2018 22:24:36 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 20C1D2BEA4; Wed, 14 Nov 2018 22:24:36 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id A24A42AEA2 for ; Wed, 14 Nov 2018 22:24:35 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id A790B6E586; Wed, 14 Nov 2018 22:24:34 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by gabe.freedesktop.org (Postfix) with ESMTPS id 9B72E6E581; Wed, 14 Nov 2018 22:24:32 +0000 (UTC) Received: from sasha-vm.mshome.net (unknown [64.114.255.114]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6F3202252A; Wed, 14 Nov 2018 22:24:32 +0000 (UTC) From: Sasha Levin To: stable@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH AUTOSEL 4.18 33/59] drm/amd/amdgpu/dm: Fix dm_dp_create_fake_mst_encoder() Date: Wed, 14 Nov 2018 17:23:05 -0500 Message-Id: <20181114222335.99339-33-sashal@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20181114222335.99339-1-sashal@kernel.org> References: <20181114222335.99339-1-sashal@kernel.org> X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Alex Deucher , Sasha Levin , dri-devel@lists.freedesktop.org, amd-gfx@lists.freedesktop.org MIME-Version: 1.0 Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" X-Virus-Scanned: ClamAV using ClamSMTP From: Lyude Paul [ Upstream commit 63237f8748bdf46dccf79ef8f98f05e9fe799162 ] [why] Removing connector reusage from DM to match the rest of the tree ended up revealing an issue that was surprisingly subtle. The original amdgpu code for DC that was submitted appears to have left a chunk in dm_dp_create_fake_mst_encoder() that tries to find a "master encoder", the likes of which isn't actually used or stored anywhere. It does so at the wrong time as well by trying to access parts of the drm_connector from the encoder init before it's actually been initialized. This results in a NULL pointer deref on MST hotplugs: [ 160.696613] BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 [ 160.697234] PGD 0 P4D 0 [ 160.697814] Oops: 0010 [#1] SMP PTI [ 160.698430] CPU: 2 PID: 64 Comm: kworker/2:1 Kdump: loaded Tainted: G O 4.19.0Lyude-Test+ #2 [ 160.699020] Hardware name: HP HP ZBook 15 G4/8275, BIOS P70 Ver. 01.22 05/17/2018 [ 160.699672] Workqueue: events_long drm_dp_mst_link_probe_work [drm_kms_helper] [ 160.700322] RIP: 0010: (null) [ 160.700920] Code: Bad RIP value. [ 160.701541] RSP: 0018:ffffc9000029fc78 EFLAGS: 00010206 [ 160.702183] RAX: 0000000000000000 RBX: ffff8804440ed468 RCX: ffff8804440e9158 [ 160.702778] RDX: 0000000000000000 RSI: ffff8804556c5700 RDI: ffff8804440ed000 [ 160.703408] RBP: ffff880458e21800 R08: 0000000000000002 R09: 000000005fca0a25 [ 160.704002] R10: ffff88045a077a3d R11: ffff88045a077a3c R12: ffff8804440ed000 [ 160.704614] R13: ffff880458e21800 R14: ffff8804440e9000 R15: ffff8804440e9000 [ 160.705260] FS: 0000000000000000(0000) GS:ffff88045f280000(0000) knlGS:0000000000000000 [ 160.705854] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 160.706478] CR2: ffffffffffffffd6 CR3: 000000000200a001 CR4: 00000000003606e0 [ 160.707124] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 160.707724] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 160.708372] Call Trace: [ 160.708998] ? dm_dp_add_mst_connector+0xed/0x1d0 [amdgpu] [ 160.709625] ? drm_dp_add_port+0x2fa/0x470 [drm_kms_helper] [ 160.710284] ? wake_up_q+0x54/0x70 [ 160.710877] ? __mutex_unlock_slowpath.isra.18+0xb3/0x110 [ 160.711512] ? drm_dp_dpcd_access+0xe7/0x110 [drm_kms_helper] [ 160.712161] ? drm_dp_send_link_address+0x155/0x1e0 [drm_kms_helper] [ 160.712762] ? drm_dp_check_and_send_link_address+0xa3/0xd0 [drm_kms_helper] [ 160.713408] ? drm_dp_mst_link_probe_work+0x4b/0x80 [drm_kms_helper] [ 160.714013] ? process_one_work+0x1a1/0x3a0 [ 160.714667] ? worker_thread+0x30/0x380 [ 160.715326] ? wq_update_unbound_numa+0x10/0x10 [ 160.715939] ? kthread+0x112/0x130 [ 160.716591] ? kthread_create_worker_on_cpu+0x70/0x70 [ 160.717262] ? ret_from_fork+0x35/0x40 [ 160.717886] Modules linked in: amdgpu(O) vfat fat snd_hda_codec_generic joydev i915 chash gpu_sched ttm i2c_algo_bit drm_kms_helper snd_hda_codec_hdmi hp_wmi syscopyarea iTCO_wdt sysfillrect sparse_keymap sysimgblt fb_sys_fops snd_hda_intel usbhid wmi_bmof drm snd_hda_codec btusb snd_hda_core intel_rapl btrtl x86_pkg_temp_thermal btbcm btintel coretemp snd_pcm crc32_pclmul bluetooth psmouse snd_timer snd pcspkr i2c_i801 mei_me i2c_core soundcore mei tpm_tis wmi tpm_tis_core hp_accel ecdh_generic lis3lv02d tpm video rfkill acpi_pad input_polldev hp_wireless pcc_cpufreq crc32c_intel serio_raw tg3 xhci_pci xhci_hcd [last unloaded: amdgpu] [ 160.720141] CR2: 0000000000000000 Somehow the connector reusage DM was using for MST connectors managed to paper over this issue entirely; hence why this was never caught until now. [how] Since this code isn't used anywhere and seems useless anyway, we can just drop it entirely. This appears to fix the issue on my HP ZBook with an AMD WX4150. Signed-off-by: Lyude Paul Reviewed-by: Harry Wentland Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin --- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c | 5 ----- 1 file changed, 5 deletions(-) diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c index ace9ad578ca0..4a748c72b534 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c @@ -295,12 +295,7 @@ dm_dp_create_fake_mst_encoder(struct amdgpu_dm_connector *connector) struct amdgpu_device *adev = dev->dev_private; struct amdgpu_encoder *amdgpu_encoder; struct drm_encoder *encoder; - const struct drm_connector_helper_funcs *connector_funcs = - connector->base.helper_private; - struct drm_encoder *enc_master = - connector_funcs->best_encoder(&connector->base); - DRM_DEBUG_KMS("enc master is %p\n", enc_master); amdgpu_encoder = kzalloc(sizeof(*amdgpu_encoder), GFP_KERNEL); if (!amdgpu_encoder) return NULL;