This is a note to let you know that I've just added the patch titled
drm/radeon: Fix deadlock on runtime suspend
to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: drm-radeon-fix-deadlock-on-runtime-suspend.patch and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From 15734feff2bdac24aa3266c437cffa42851990e3 Mon Sep 17 00:00:00 2001
From: Lukas Wunner lukas@wunner.de Date: Sun, 11 Feb 2018 10:38:28 +0100 Subject: drm/radeon: Fix deadlock on runtime suspend
From: Lukas Wunner lukas@wunner.de
commit 15734feff2bdac24aa3266c437cffa42851990e3 upstream.
radeon'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 radeon'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.
Stack trace for posterity:
INFO: task kworker/0:3:31847 blocked for more than 120 seconds Workqueue: events output_poll_execute [drm_kms_helper] Call Trace: schedule+0x3c/0x90 rpm_resume+0x1e2/0x690 __pm_runtime_resume+0x3f/0x60 radeon_lvds_detect+0x39/0xf0 [radeon] output_poll_execute+0xda/0x1e0 [drm_kms_helper] process_one_work+0x14b/0x440 worker_thread+0x48/0x4a0
INFO: task kworker/2:0:10493 blocked for more than 120 seconds. Workqueue: pm pm_runtime_work Call Trace: schedule+0x3c/0x90 schedule_timeout+0x1b3/0x240 wait_for_common+0xc2/0x180 wait_for_completion+0x1d/0x20 flush_work+0xfc/0x1a0 __cancel_work_timer+0xa5/0x1d0 cancel_delayed_work_sync+0x13/0x20 drm_kms_helper_poll_disable+0x1f/0x30 [drm_kms_helper] radeon_pmops_runtime_suspend+0x3d/0xa0 [radeon] pci_pm_runtime_suspend+0x61/0x1a0 vga_switcheroo_runtime_suspend+0x21/0x70 __rpm_callback+0x32/0x70 rpm_callback+0x24/0x80 rpm_suspend+0x12b/0x640 pm_runtime_work+0x6f/0xb0 process_one_work+0x14b/0x440 worker_thread+0x48/0x4a0
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=94147 Fixes: 10ebc0bc0934 ("drm/radeon: add runtime PM support (v2)") Cc: stable@vger.kernel.org # v3.13+: 27d4ee03078a: workqueue: Allow retrieval of current task's work struct Cc: stable@vger.kernel.org # v3.13+: 25c058ccaf2e: drm: Allow determining if current task is output poll worker Cc: Ismo Toijala ismo.toijala@gmail.com Cc: Alex Deucher alexander.deucher@amd.com Cc: Dave Airlie airlied@redhat.com Reviewed-by: Lyude Paul lyude@redhat.com Signed-off-by: Lukas Wunner lukas@wunner.de Link: https://patchwork.freedesktop.org/patch/msgid/64ea02c44f91dda19bc563902b97bb... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/gpu/drm/radeon/radeon_connectors.c | 74 +++++++++++++++++++---------- 1 file changed, 49 insertions(+), 25 deletions(-)
--- a/drivers/gpu/drm/radeon/radeon_connectors.c +++ b/drivers/gpu/drm/radeon/radeon_connectors.c @@ -891,9 +891,11 @@ radeon_lvds_detect(struct drm_connector 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 radeon_encoder *radeon_encoder = to_radeon_encoder(encoder); @@ -916,8 +918,12 @@ radeon_lvds_detect(struct drm_connector /* check acpi lid status ??? */
radeon_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; }
@@ -1020,9 +1026,11 @@ radeon_vga_detect(struct drm_connector * 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 = radeon_best_single_encoder(connector); if (!encoder) @@ -1089,8 +1097,10 @@ radeon_vga_detect(struct drm_connector * radeon_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; } @@ -1153,9 +1163,11 @@ radeon_tv_detect(struct drm_connector *c if (!radeon_connector->dac_load_detect) return ret;
- 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 = radeon_best_single_encoder(connector); if (!encoder) @@ -1167,8 +1179,12 @@ radeon_tv_detect(struct drm_connector *c if (ret == connector_status_connected) ret = radeon_connector_analog_encoder_conflict_solve(connector, encoder, ret, false); radeon_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; }
@@ -1230,9 +1246,11 @@ radeon_dvi_detect(struct drm_connector * 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 (radeon_connector->detected_hpd_without_ddc) { force = true; @@ -1415,8 +1433,10 @@ out: }
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; } @@ -1666,9 +1686,11 @@ radeon_dp_detect(struct drm_connector *c if (radeon_dig_connector->is_mst) return connector_status_disconnected;
- 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 && radeon_check_hpd_status_unchanged(connector)) { ret = connector->status; @@ -1755,8 +1777,10 @@ radeon_dp_detect(struct drm_connector *c }
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; }
Patches currently in stable-queue which might be from lukas@wunner.de are
queue-4.4/workqueue-allow-retrieval-of-current-task-s-work-struct.patch queue-4.4/drm-radeon-fix-deadlock-on-runtime-suspend.patch queue-4.4/drm-amdgpu-fix-deadlock-on-runtime-suspend.patch queue-4.4/drm-allow-determining-if-current-task-is-output-poll-worker.patch queue-4.4/drm-nouveau-fix-deadlock-on-runtime-suspend.patch