From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:37432 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933348AbeCPPbU (ORCPT ); Fri, 16 Mar 2018 11:31:20 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alex Deucher , Mike Lothian , Lyude Paul , Lukas Wunner Subject: [PATCH 4.9 11/86] drm/amdgpu: Fix deadlock on runtime suspend Date: Fri, 16 Mar 2018 16:22:34 +0100 Message-Id: <20180316152318.034552608@linuxfoundation.org> In-Reply-To: <20180316152317.167709497@linuxfoundation.org> References: <20180316152317.167709497@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Lukas Wunner commit aa0aad57909eb321746325951d66af88a83bc956 upstream. amdgpu's ->runtime_suspend hook calls drm_kms_helper_poll_disable(), which waits for the output poll worker to finish if it's running. The output poll worker meanwhile calls pm_runtime_get_sync() in amdgpu's ->detect hooks, which waits for the ongoing suspend to finish, causing a deadlock. Fix by not acquiring a runtime PM ref if the ->detect hooks are called in the output poll worker's context. This is safe because the poll worker is only enabled while runtime active and we know that ->runtime_suspend waits for it to finish. Fixes: d38ceaf99ed0 ("drm/amdgpu: add core driver (v4)") Cc: stable@vger.kernel.org # v4.2+: 27d4ee03078a: workqueue: Allow retrieval of current task's work struct Cc: stable@vger.kernel.org # v4.2+: 25c058ccaf2e: drm: Allow determining if current task is output poll worker Cc: Alex Deucher Tested-by: Mike Lothian Reviewed-by: Lyude Paul Signed-off-by: Lukas Wunner Link: https://patchwork.freedesktop.org/patch/msgid/4c9bf72aacae1eef062bd134cd112e0770a7f121.1518338789.git.lukas@wunner.de Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c | 58 ++++++++++++++++--------- 1 file changed, 38 insertions(+), 20 deletions(-) --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c @@ -739,9 +739,11 @@ amdgpu_connector_lvds_detect(struct drm_ enum drm_connector_status ret = connector_status_disconnected; int r; - r = pm_runtime_get_sync(connector->dev->dev); - if (r < 0) - return connector_status_disconnected; + if (!drm_kms_helper_is_poll_worker()) { + r = pm_runtime_get_sync(connector->dev->dev); + if (r < 0) + return connector_status_disconnected; + } if (encoder) { struct amdgpu_encoder *amdgpu_encoder = to_amdgpu_encoder(encoder); @@ -760,8 +762,12 @@ amdgpu_connector_lvds_detect(struct drm_ /* check acpi lid status ??? */ amdgpu_connector_update_scratch_regs(connector, ret); - pm_runtime_mark_last_busy(connector->dev->dev); - pm_runtime_put_autosuspend(connector->dev->dev); + + if (!drm_kms_helper_is_poll_worker()) { + pm_runtime_mark_last_busy(connector->dev->dev); + pm_runtime_put_autosuspend(connector->dev->dev); + } + return ret; } @@ -871,9 +877,11 @@ amdgpu_connector_vga_detect(struct drm_c enum drm_connector_status ret = connector_status_disconnected; int r; - r = pm_runtime_get_sync(connector->dev->dev); - if (r < 0) - return connector_status_disconnected; + if (!drm_kms_helper_is_poll_worker()) { + r = pm_runtime_get_sync(connector->dev->dev); + if (r < 0) + return connector_status_disconnected; + } encoder = amdgpu_connector_best_single_encoder(connector); if (!encoder) @@ -927,8 +935,10 @@ amdgpu_connector_vga_detect(struct drm_c amdgpu_connector_update_scratch_regs(connector, ret); out: - pm_runtime_mark_last_busy(connector->dev->dev); - pm_runtime_put_autosuspend(connector->dev->dev); + if (!drm_kms_helper_is_poll_worker()) { + pm_runtime_mark_last_busy(connector->dev->dev); + pm_runtime_put_autosuspend(connector->dev->dev); + } return ret; } @@ -991,9 +1001,11 @@ amdgpu_connector_dvi_detect(struct drm_c enum drm_connector_status ret = connector_status_disconnected; bool dret = false, broken_edid = false; - r = pm_runtime_get_sync(connector->dev->dev); - if (r < 0) - return connector_status_disconnected; + if (!drm_kms_helper_is_poll_worker()) { + r = pm_runtime_get_sync(connector->dev->dev); + if (r < 0) + return connector_status_disconnected; + } if (!force && amdgpu_connector_check_hpd_status_unchanged(connector)) { ret = connector->status; @@ -1118,8 +1130,10 @@ out: amdgpu_connector_update_scratch_regs(connector, ret); exit: - pm_runtime_mark_last_busy(connector->dev->dev); - pm_runtime_put_autosuspend(connector->dev->dev); + if (!drm_kms_helper_is_poll_worker()) { + pm_runtime_mark_last_busy(connector->dev->dev); + pm_runtime_put_autosuspend(connector->dev->dev); + } return ret; } @@ -1362,9 +1376,11 @@ amdgpu_connector_dp_detect(struct drm_co struct drm_encoder *encoder = amdgpu_connector_best_single_encoder(connector); int r; - r = pm_runtime_get_sync(connector->dev->dev); - if (r < 0) - return connector_status_disconnected; + if (!drm_kms_helper_is_poll_worker()) { + r = pm_runtime_get_sync(connector->dev->dev); + if (r < 0) + return connector_status_disconnected; + } if (!force && amdgpu_connector_check_hpd_status_unchanged(connector)) { ret = connector->status; @@ -1432,8 +1448,10 @@ amdgpu_connector_dp_detect(struct drm_co amdgpu_connector_update_scratch_regs(connector, ret); out: - pm_runtime_mark_last_busy(connector->dev->dev); - pm_runtime_put_autosuspend(connector->dev->dev); + if (!drm_kms_helper_is_poll_worker()) { + pm_runtime_mark_last_busy(connector->dev->dev); + pm_runtime_put_autosuspend(connector->dev->dev); + } return ret; }