The patch below does not apply to the 4.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From d61a5c1063515e855bedb1b81e20e50b0ac3541e Mon Sep 17 00:00:00 2001
From: Lukas Wunner lukas@wunner.de Date: Sun, 11 Feb 2018 10:38:28 +0100 Subject: [PATCH] drm/nouveau: Fix deadlock on runtime suspend
nouveau'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 nouveau_connector_detect() which waits for the ongoing suspend to finish, causing a deadlock.
Fix by not acquiring a runtime PM ref if nouveau_connector_detect() is 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.
Other contexts calling nouveau_connector_detect() do require a runtime PM ref, these comprise:
status_store() drm sysfs interface ->fill_modes drm callback drm_fb_helper_probe_connector_modes() drm_mode_getconnector() nouveau_connector_hotplug() nouveau_display_hpd_work() nv17_tv_set_property()
Stack trace for posterity:
INFO: task kworker/0:1:58 blocked for more than 120 seconds. Workqueue: events output_poll_execute [drm_kms_helper] Call Trace: schedule+0x28/0x80 rpm_resume+0x107/0x6e0 __pm_runtime_resume+0x47/0x70 nouveau_connector_detect+0x7e/0x4a0 [nouveau] nouveau_connector_detect_lvds+0x132/0x180 [nouveau] drm_helper_probe_detect_ctx+0x85/0xd0 [drm_kms_helper] output_poll_execute+0x11e/0x1c0 [drm_kms_helper] process_one_work+0x184/0x380 worker_thread+0x2e/0x390
INFO: task kworker/0:2:252 blocked for more than 120 seconds. Workqueue: pm pm_runtime_work Call Trace: schedule+0x28/0x80 schedule_timeout+0x1e3/0x370 wait_for_completion+0x123/0x190 flush_work+0x142/0x1c0 nouveau_pmops_runtime_suspend+0x7e/0xd0 [nouveau] pci_pm_runtime_suspend+0x5c/0x180 vga_switcheroo_runtime_suspend+0x1e/0xa0 __rpm_callback+0xc1/0x200 rpm_callback+0x1f/0x70 rpm_suspend+0x13c/0x640 pm_runtime_work+0x6e/0x90 process_one_work+0x184/0x380 worker_thread+0x2e/0x390
Bugzilla: https://bugs.archlinux.org/task/53497 Bugzilla: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=870523 Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=70388#c33 Fixes: 5addcf0a5f0f ("nouveau: add runtime PM support (v0.9)") Cc: stable@vger.kernel.org # v3.12+: 27d4ee03078a: workqueue: Allow retrieval of current task's work struct Cc: stable@vger.kernel.org # v3.12+: 25c058ccaf2e: drm: Allow determining if current task is output poll worker Cc: Ben Skeggs bskeggs@redhat.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/b7d2cbb609a80f59ccabfdf479b9d5...
diff --git a/drivers/gpu/drm/nouveau/nouveau_connector.c b/drivers/gpu/drm/nouveau/nouveau_connector.c index 69d6e61a01ec..6ed9cb053dfa 100644 --- a/drivers/gpu/drm/nouveau/nouveau_connector.c +++ b/drivers/gpu/drm/nouveau/nouveau_connector.c @@ -570,9 +570,15 @@ nouveau_connector_detect(struct drm_connector *connector, bool force) nv_connector->edid = NULL; }
- ret = pm_runtime_get_sync(connector->dev->dev); - if (ret < 0 && ret != -EACCES) - return conn_status; + /* Outputs are only polled while runtime active, so acquiring a + * runtime PM ref here is unnecessary (and would deadlock upon + * runtime suspend because it waits for polling to finish). + */ + if (!drm_kms_helper_is_poll_worker()) { + ret = pm_runtime_get_sync(connector->dev->dev); + if (ret < 0 && ret != -EACCES) + return conn_status; + }
nv_encoder = nouveau_connector_ddc_detect(connector); if (nv_encoder && (i2c = nv_encoder->i2c) != NULL) { @@ -647,8 +653,10 @@ nouveau_connector_detect(struct drm_connector *connector, bool force)
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 conn_status; }
Hi Greg,
On Mon, Feb 26, 2018 at 05:07:55PM +0100, gregkh@linuxfoundation.org wrote:
The patch below does not apply to the 4.14-stable tree.
The patch applies just fine, but it has two prerequisites, as specified in the commit message:
Cc: stable@vger.kernel.org # v3.12+: 27d4ee03078a: workqueue: Allow retrieval of current task's work struct Cc: stable@vger.kernel.org # v3.12+: 25c058ccaf2e: drm: Allow determining if current task is output poll worker
The radeon and amdgpu patches have the same prerequisites.
Thanks,
Lukas
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From d61a5c1063515e855bedb1b81e20e50b0ac3541e Mon Sep 17 00:00:00 2001 From: Lukas Wunner lukas@wunner.de Date: Sun, 11 Feb 2018 10:38:28 +0100 Subject: [PATCH] drm/nouveau: Fix deadlock on runtime suspend
nouveau'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 nouveau_connector_detect() which waits for the ongoing suspend to finish, causing a deadlock.
Fix by not acquiring a runtime PM ref if nouveau_connector_detect() is 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.
Other contexts calling nouveau_connector_detect() do require a runtime PM ref, these comprise:
status_store() drm sysfs interface ->fill_modes drm callback drm_fb_helper_probe_connector_modes() drm_mode_getconnector() nouveau_connector_hotplug() nouveau_display_hpd_work() nv17_tv_set_property()
Stack trace for posterity:
INFO: task kworker/0:1:58 blocked for more than 120 seconds. Workqueue: events output_poll_execute [drm_kms_helper] Call Trace: schedule+0x28/0x80 rpm_resume+0x107/0x6e0 __pm_runtime_resume+0x47/0x70 nouveau_connector_detect+0x7e/0x4a0 [nouveau] nouveau_connector_detect_lvds+0x132/0x180 [nouveau] drm_helper_probe_detect_ctx+0x85/0xd0 [drm_kms_helper] output_poll_execute+0x11e/0x1c0 [drm_kms_helper] process_one_work+0x184/0x380 worker_thread+0x2e/0x390
INFO: task kworker/0:2:252 blocked for more than 120 seconds. Workqueue: pm pm_runtime_work Call Trace: schedule+0x28/0x80 schedule_timeout+0x1e3/0x370 wait_for_completion+0x123/0x190 flush_work+0x142/0x1c0 nouveau_pmops_runtime_suspend+0x7e/0xd0 [nouveau] pci_pm_runtime_suspend+0x5c/0x180 vga_switcheroo_runtime_suspend+0x1e/0xa0 __rpm_callback+0xc1/0x200 rpm_callback+0x1f/0x70 rpm_suspend+0x13c/0x640 pm_runtime_work+0x6e/0x90 process_one_work+0x184/0x380 worker_thread+0x2e/0x390
Bugzilla: https://bugs.archlinux.org/task/53497 Bugzilla: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=870523 Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=70388#c33 Fixes: 5addcf0a5f0f ("nouveau: add runtime PM support (v0.9)") Cc: stable@vger.kernel.org # v3.12+: 27d4ee03078a: workqueue: Allow retrieval of current task's work struct Cc: stable@vger.kernel.org # v3.12+: 25c058ccaf2e: drm: Allow determining if current task is output poll worker Cc: Ben Skeggs bskeggs@redhat.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/b7d2cbb609a80f59ccabfdf479b9d5...
diff --git a/drivers/gpu/drm/nouveau/nouveau_connector.c b/drivers/gpu/drm/nouveau/nouveau_connector.c index 69d6e61a01ec..6ed9cb053dfa 100644 --- a/drivers/gpu/drm/nouveau/nouveau_connector.c +++ b/drivers/gpu/drm/nouveau/nouveau_connector.c @@ -570,9 +570,15 @@ nouveau_connector_detect(struct drm_connector *connector, bool force) nv_connector->edid = NULL; }
- ret = pm_runtime_get_sync(connector->dev->dev);
- if (ret < 0 && ret != -EACCES)
return conn_status;
- /* Outputs are only polled while runtime active, so acquiring a
* runtime PM ref here is unnecessary (and would deadlock upon
* runtime suspend because it waits for polling to finish).
*/
- if (!drm_kms_helper_is_poll_worker()) {
ret = pm_runtime_get_sync(connector->dev->dev);
if (ret < 0 && ret != -EACCES)
return conn_status;
- }
nv_encoder = nouveau_connector_ddc_detect(connector); if (nv_encoder && (i2c = nv_encoder->i2c) != NULL) { @@ -647,8 +653,10 @@ nouveau_connector_detect(struct drm_connector *connector, bool force) 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 conn_status; }
On Mon, Feb 26, 2018 at 05:13:51PM +0100, Lukas Wunner wrote:
Hi Greg,
On Mon, Feb 26, 2018 at 05:07:55PM +0100, gregkh@linuxfoundation.org wrote:
The patch below does not apply to the 4.14-stable tree.
The patch applies just fine, but it has two prerequisites, as specified in the commit message:
Cc: stable@vger.kernel.org # v3.12+: 27d4ee03078a: workqueue: Allow retrieval of current task's work struct Cc: stable@vger.kernel.org # v3.12+: 25c058ccaf2e: drm: Allow determining if current task is output poll worker
The radeon and amdgpu patches have the same prerequisites.
Doh, I missed that, sorry. Now fixed up.
greg k-h
linux-stable-mirror@lists.linaro.org