From: Sean Paul <sean@poorly.run>
To: dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org
Cc: daniel.vetter@ffwll.ch, Sean Paul <seanpaul@chromium.org>
Subject: [Intel-gfx] [PATCH v3 07/12] drm/i915: Protect workers against disappearing connectors
Date: Fri, 17 Jan 2020 14:30:58 -0500 [thread overview]
Message-ID: <20200117193103.156821-8-sean@poorly.run> (raw)
In-Reply-To: <20200117193103.156821-1-sean@poorly.run>
From: Sean Paul <seanpaul@chromium.org>
This patch adds some protection against connectors being destroyed
before the HDCP workers are finished.
For check_work, we do a synchronous cancel after the connector is
unregistered which will ensure that it is finished before destruction.
In the case of prop_work, we can't do a synchronous wait since it needs
to take connection_mutex which could cause deadlock. Instead, we'll take
a reference on the connector when scheduling prop_work and give it up
once we're done.
Reviewed-by: Ramalingam C <ramalingam.c@intel.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20191212190230.188505-8-sean@poorly.run #v2
Changes in v2:
- Added to the set
Changes in v3:
- Change the WARN_ON condition in intel_hdcp_cleanup to allow for
initializing connectors as well
---
drivers/gpu/drm/i915/display/intel_hdcp.c | 43 ++++++++++++++++++++---
1 file changed, 38 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.c b/drivers/gpu/drm/i915/display/intel_hdcp.c
index 798e7e1a19fc..fabacfb1b644 100644
--- a/drivers/gpu/drm/i915/display/intel_hdcp.c
+++ b/drivers/gpu/drm/i915/display/intel_hdcp.c
@@ -863,8 +863,10 @@ static void intel_hdcp_update_value(struct intel_connector *connector,
return;
hdcp->value = value;
- if (update_property)
+ if (update_property) {
+ drm_connector_get(&connector->base);
schedule_work(&hdcp->prop_work);
+ }
}
/* Implements Part 3 of the HDCP authorization procedure */
@@ -954,6 +956,8 @@ static void intel_hdcp_prop_work(struct work_struct *work)
mutex_unlock(&hdcp->mutex);
drm_modeset_unlock(&dev->mode_config.connection_mutex);
+
+ drm_connector_put(&connector->base);
}
bool is_hdcp_supported(struct drm_i915_private *dev_priv, enum port port)
@@ -1802,6 +1806,9 @@ static void intel_hdcp_check_work(struct work_struct *work)
check_work);
struct intel_connector *connector = intel_hdcp_to_connector(hdcp);
+ if (drm_connector_is_unregistered(&connector->base))
+ return;
+
if (!intel_hdcp2_check_link(connector))
schedule_delayed_work(&hdcp->check_work,
DRM_HDCP2_CHECK_PERIOD_MS);
@@ -2076,12 +2083,38 @@ void intel_hdcp_component_fini(struct drm_i915_private *dev_priv)
void intel_hdcp_cleanup(struct intel_connector *connector)
{
- if (!connector->hdcp.shim)
+ struct intel_hdcp *hdcp = &connector->hdcp;
+
+ if (!hdcp->shim)
return;
- mutex_lock(&connector->hdcp.mutex);
- kfree(connector->hdcp.port_data.streams);
- mutex_unlock(&connector->hdcp.mutex);
+ /*
+ * If the connector is registered, it's possible userspace could kick
+ * off another HDCP enable, which would re-spawn the workers.
+ */
+ WARN_ON(connector->base.registration_state == DRM_CONNECTOR_REGISTERED);
+
+ /*
+ * Now that the connector is not registered, check_work won't be run,
+ * but cancel any outstanding instances of it
+ */
+ cancel_delayed_work_sync(&hdcp->check_work);
+
+ /*
+ * We don't cancel prop_work in the same way as check_work since it
+ * requires connection_mutex which could be held while calling this
+ * function. Instead, we rely on the connector references grabbed before
+ * scheduling prop_work to ensure the connector is alive when prop_work
+ * is run. So if we're in the destroy path (which is where this
+ * function should be called), we're "guaranteed" that prop_work is not
+ * active (tl;dr This Should Never Happen).
+ */
+ WARN_ON(work_pending(&hdcp->prop_work));
+
+ mutex_lock(&hdcp->mutex);
+ kfree(hdcp->port_data.streams);
+ hdcp->shim = NULL;
+ mutex_unlock(&hdcp->mutex);
}
void intel_hdcp_atomic_check(struct drm_connector *connector,
--
Sean Paul, Software Engineer, Google / Chromium OS
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next prev parent reply other threads:[~2020-01-17 19:31 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-17 19:30 [Intel-gfx] [PATCH v3 00/12] drm/i915: Add support for HDCP 1.4 over MST connectors Sean Paul
2020-01-17 19:30 ` [Intel-gfx] [PATCH v3 01/12] drm/i915: Fix sha_text population code Sean Paul
2020-01-19 15:26 ` Sasha Levin
2020-01-17 19:30 ` [Intel-gfx] [PATCH v3 02/12] drm/i915: Clear the repeater bit on HDCP disable Sean Paul
2020-01-19 15:26 ` Sasha Levin
2020-01-17 19:30 ` [Intel-gfx] [PATCH v3 03/12] drm/i915: WARN if HDCP signalling is enabled upon disable Sean Paul
2020-01-17 19:30 ` [Intel-gfx] [PATCH v3 04/12] drm/i915: Intercept Aksv writes in the aux hooks Sean Paul
2020-01-17 19:30 ` [Intel-gfx] [PATCH v3 05/12] drm/i915: Use the cpu_transcoder in intel_hdcp to toggle HDCP signalling Sean Paul
2020-01-17 19:30 ` [Intel-gfx] [PATCH v3 06/12] drm/i915: Factor out hdcp->value assignments Sean Paul
2020-01-17 19:30 ` Sean Paul [this message]
2020-01-17 19:30 ` [Intel-gfx] [PATCH v3 08/12] drm/i915: Don't fully disable HDCP on a port if multiple pipes are using it Sean Paul
2020-02-02 19:03 ` Ramalingam C
2020-02-18 22:07 ` Sean Paul
2020-01-17 19:31 ` [Intel-gfx] [PATCH v3 09/12] drm/i915: Support DP MST in enc_to_dig_port() function Sean Paul
2020-01-17 19:31 ` [Intel-gfx] [PATCH v3 10/12] drm/i915: Use ddi_update_pipe in intel_dp_mst Sean Paul
2020-01-17 19:31 ` [Intel-gfx] [PATCH v3 11/12] drm/i915: Factor out HDCP shim functions from dp for use by dp_mst Sean Paul
2020-01-17 19:31 ` [Intel-gfx] [PATCH v3 12/12] drm/i915: Add HDCP 1.4 support for MST connectors Sean Paul
2020-01-18 2:08 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for drm/i915: Add support for HDCP 1.4 over MST connectors (rev3) Patchwork
2020-01-18 3:18 ` [Intel-gfx] ✓ Fi.CI.BAT: success " Patchwork
2020-01-18 3:18 ` [Intel-gfx] ✗ Fi.CI.BUILD: warning " Patchwork
2020-01-20 19:46 ` [Intel-gfx] ✓ Fi.CI.IGT: success " Patchwork
2020-01-27 14:06 ` [Intel-gfx] [PATCH v3 00/12] drm/i915: Add support for HDCP 1.4 over MST connectors Sean Paul
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