FAILED: patch "[PATCH] platform/chrome: cros_ec: Unregister notifier in" failed to apply to 6.1-stable tree

FAILED: patch "[PATCH] platform/chrome: cros_ec: Unregister notifier in" failed to apply to 6.1-stable tree

[gregkh]

The patch below does not apply to the 6.1-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>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x e2374953461947eee49f69b3e3204ff080ef31b1
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2025082112-exemplary-explode-1646@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From e2374953461947eee49f69b3e3204ff080ef31b1 Mon Sep 17 00:00:00 2001
From: Tzung-Bi Shih <tzungbi@kernel.org>
Date: Tue, 22 Jul 2025 12:05:13 +0000
Subject: [PATCH] platform/chrome: cros_ec: Unregister notifier in
 cros_ec_unregister()

The blocking notifier is registered in cros_ec_register(); however, it
isn't unregistered in cros_ec_unregister().

Fix it.

Fixes: 42cd0ab476e2 ("platform/chrome: cros_ec: Query EC protocol version if EC transitions between RO/RW")
Cc: stable@vger.kernel.org
Reviewed-by: Benson Leung <bleung@chromium.org>
Link: https://lore.kernel.org/r/20250722120513.234031-1-tzungbi@kernel.org
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>

diff --git a/drivers/platform/chrome/cros_ec.c b/drivers/platform/chrome/cros_ec.c
index 110771a8645e..fd58781a2fb7 100644
--- a/drivers/platform/chrome/cros_ec.c
+++ b/drivers/platform/chrome/cros_ec.c
@@ -318,6 +318,9 @@ EXPORT_SYMBOL(cros_ec_register);
  */
 void cros_ec_unregister(struct cros_ec_device *ec_dev)
 {
+	if (ec_dev->mkbp_event_supported)
+		blocking_notifier_chain_unregister(&ec_dev->event_notifier,
+						   &ec_dev->notifier_ready);
 	platform_device_unregister(ec_dev->pd);
 	platform_device_unregister(ec_dev->ec);
 	mutex_destroy(&ec_dev->lock);

[PATCH 6.1.y 1/3] platform/chrome: cros_ec: Use per-device lockdep key

[Sasha Levin]

From: Chen-Yu Tsai <wenst@chromium.org>

[ Upstream commit 961a325becd9a142ae5c8b258e5c2f221f8bfac8 ]

Lockdep reports a bogus possible deadlock on MT8192 Chromebooks due to
the following lock sequences:

1. lock(i2c_register_adapter) [1]; lock(&ec_dev->lock)
2. lock(&ec_dev->lock); lock(prepare_lock);

The actual dependency chains are much longer. The shortened version
looks somewhat like:

1. cros-ec-rpmsg on mtk-scp
   ec_dev->lock -> prepare_lock
2. In rt5682_i2c_probe() on native I2C bus:
   prepare_lock -> regmap->lock -> (possibly) i2c_adapter->bus_lock
3. In rt5682_i2c_probe() on native I2C bus:
   regmap->lock -> i2c_adapter->bus_lock
4. In sbs_probe() on i2c-cros-ec-tunnel I2C bus attached on cros-ec:
   i2c_adapter->bus_lock -> ec_dev->lock

While lockdep is correct that the shared lockdep classes have a circular
dependency, it is bogus because

  a) 2+3 happen on a native I2C bus
  b) 4 happens on the actual EC on ChromeOS devices
  c) 1 happens on the SCP coprocessor on MediaTek Chromebooks that just
     happens to expose a cros-ec interface, but does not have an
     i2c-cros-ec-tunnel I2C bus

In short, the "dependencies" are actually on different devices.

Setup a per-device lockdep key for cros_ec devices so lockdep can tell
the two instances apart. This helps with getting rid of the bogus
lockdep warning. For ChromeOS devices that only have one cros-ec
instance this doesn't change anything.

Also add a missing mutex_destroy, just to make the teardown complete.

[1] This is likely the per I2C bus lock with shared lockdep class

Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Link: https://lore.kernel.org/r/20230111074146.2624496-1-wenst@chromium.org
Stable-dep-of: e23749534619 ("platform/chrome: cros_ec: Unregister notifier in cros_ec_unregister()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/platform/chrome/cros_ec.c           | 14 +++++++++++---
 include/linux/platform_data/cros_ec_proto.h |  4 ++++
 2 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/drivers/platform/chrome/cros_ec.c b/drivers/platform/chrome/cros_ec.c
index ec733f683f34..4ae57820afd5 100644
--- a/drivers/platform/chrome/cros_ec.c
+++ b/drivers/platform/chrome/cros_ec.c
@@ -198,12 +198,14 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
 	if (!ec_dev->dout)
 		return -ENOMEM;
 
+	lockdep_register_key(&ec_dev->lockdep_key);
 	mutex_init(&ec_dev->lock);
+	lockdep_set_class(&ec_dev->lock, &ec_dev->lockdep_key);
 
 	err = cros_ec_query_all(ec_dev);
 	if (err) {
 		dev_err(dev, "Cannot identify the EC: error %d\n", err);
-		return err;
+		goto destroy_mutex;
 	}
 
 	if (ec_dev->irq > 0) {
@@ -215,7 +217,7 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
 		if (err) {
 			dev_err(dev, "Failed to request IRQ %d: %d\n",
 				ec_dev->irq, err);
-			return err;
+			goto destroy_mutex;
 		}
 	}
 
@@ -226,7 +228,8 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
 	if (IS_ERR(ec_dev->ec)) {
 		dev_err(ec_dev->dev,
 			"Failed to create CrOS EC platform device\n");
-		return PTR_ERR(ec_dev->ec);
+		err = PTR_ERR(ec_dev->ec);
+		goto destroy_mutex;
 	}
 
 	if (ec_dev->max_passthru) {
@@ -292,6 +295,9 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
 exit:
 	platform_device_unregister(ec_dev->ec);
 	platform_device_unregister(ec_dev->pd);
+destroy_mutex:
+	mutex_destroy(&ec_dev->lock);
+	lockdep_unregister_key(&ec_dev->lockdep_key);
 	return err;
 }
 EXPORT_SYMBOL(cros_ec_register);
@@ -309,6 +315,8 @@ void cros_ec_unregister(struct cros_ec_device *ec_dev)
 	if (ec_dev->pd)
 		platform_device_unregister(ec_dev->pd);
 	platform_device_unregister(ec_dev->ec);
+	mutex_destroy(&ec_dev->lock);
+	lockdep_unregister_key(&ec_dev->lockdep_key);
 }
 EXPORT_SYMBOL(cros_ec_unregister);
 
diff --git a/include/linux/platform_data/cros_ec_proto.h b/include/linux/platform_data/cros_ec_proto.h
index e43107e0bee1..2bf307e74490 100644
--- a/include/linux/platform_data/cros_ec_proto.h
+++ b/include/linux/platform_data/cros_ec_proto.h
@@ -9,6 +9,7 @@
 #define __LINUX_CROS_EC_PROTO_H
 
 #include <linux/device.h>
+#include <linux/lockdep_types.h>
 #include <linux/mutex.h>
 #include <linux/notifier.h>
 
@@ -116,6 +117,8 @@ struct cros_ec_command {
  *            command. The caller should check msg.result for the EC's result
  *            code.
  * @pkt_xfer: Send packet to EC and get response.
+ * @lockdep_key: Lockdep class for each instance. Unused if CONFIG_LOCKDEP is
+ *		 not enabled.
  * @lock: One transaction at a time.
  * @mkbp_event_supported: 0 if MKBP not supported. Otherwise its value is
  *                        the maximum supported version of the MKBP host event
@@ -160,6 +163,7 @@ struct cros_ec_device {
 			struct cros_ec_command *msg);
 	int (*pkt_xfer)(struct cros_ec_device *ec,
 			struct cros_ec_command *msg);
+	struct lock_class_key lockdep_key;
 	struct mutex lock;
 	u8 mkbp_event_supported;
 	bool host_sleep_v1;
-- 
2.50.1

[PATCH 6.1.y 2/3] platform/chrome: cros_ec: remove unneeded label and if-condition

[Sasha Levin]

From: Tzung-Bi Shih <tzungbi@kernel.org>

[ Upstream commit 554ec02c97254962bbb0a8776c3160d294fc7e51 ]

Both `ec_dev->ec` and `ec_dev->pd` are initialized to NULL at the
beginning of cros_ec_register().  Also, platform_device_unregister()
takes care if the given platform_device is NULL.

Remove the unneeded goto-label and if-condition.

Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Link: https://lore.kernel.org/r/20230308031247.2866401-1-tzungbi@kernel.org
Stable-dep-of: e23749534619 ("platform/chrome: cros_ec: Unregister notifier in cros_ec_unregister()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/platform/chrome/cros_ec.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/drivers/platform/chrome/cros_ec.c b/drivers/platform/chrome/cros_ec.c
index 4ae57820afd5..6d997c59376d 100644
--- a/drivers/platform/chrome/cros_ec.c
+++ b/drivers/platform/chrome/cros_ec.c
@@ -205,7 +205,7 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
 	err = cros_ec_query_all(ec_dev);
 	if (err) {
 		dev_err(dev, "Cannot identify the EC: error %d\n", err);
-		goto destroy_mutex;
+		goto exit;
 	}
 
 	if (ec_dev->irq > 0) {
@@ -217,7 +217,7 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
 		if (err) {
 			dev_err(dev, "Failed to request IRQ %d: %d\n",
 				ec_dev->irq, err);
-			goto destroy_mutex;
+			goto exit;
 		}
 	}
 
@@ -229,7 +229,7 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
 		dev_err(ec_dev->dev,
 			"Failed to create CrOS EC platform device\n");
 		err = PTR_ERR(ec_dev->ec);
-		goto destroy_mutex;
+		goto exit;
 	}
 
 	if (ec_dev->max_passthru) {
@@ -295,7 +295,6 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
 exit:
 	platform_device_unregister(ec_dev->ec);
 	platform_device_unregister(ec_dev->pd);
-destroy_mutex:
 	mutex_destroy(&ec_dev->lock);
 	lockdep_unregister_key(&ec_dev->lockdep_key);
 	return err;
@@ -312,8 +311,7 @@ EXPORT_SYMBOL(cros_ec_register);
  */
 void cros_ec_unregister(struct cros_ec_device *ec_dev)
 {
-	if (ec_dev->pd)
-		platform_device_unregister(ec_dev->pd);
+	platform_device_unregister(ec_dev->pd);
 	platform_device_unregister(ec_dev->ec);
 	mutex_destroy(&ec_dev->lock);
 	lockdep_unregister_key(&ec_dev->lockdep_key);
-- 
2.50.1

[PATCH 6.1.y 3/3] platform/chrome: cros_ec: Unregister notifier in cros_ec_unregister()

[Sasha Levin]

From: Tzung-Bi Shih <tzungbi@kernel.org>

[ Upstream commit e2374953461947eee49f69b3e3204ff080ef31b1 ]

The blocking notifier is registered in cros_ec_register(); however, it
isn't unregistered in cros_ec_unregister().

Fix it.

Fixes: 42cd0ab476e2 ("platform/chrome: cros_ec: Query EC protocol version if EC transitions between RO/RW")
Cc: stable@vger.kernel.org
Reviewed-by: Benson Leung <bleung@chromium.org>
Link: https://lore.kernel.org/r/20250722120513.234031-1-tzungbi@kernel.org
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/platform/chrome/cros_ec.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/platform/chrome/cros_ec.c b/drivers/platform/chrome/cros_ec.c
index 6d997c59376d..fec99cdf6127 100644
--- a/drivers/platform/chrome/cros_ec.c
+++ b/drivers/platform/chrome/cros_ec.c
@@ -311,6 +311,9 @@ EXPORT_SYMBOL(cros_ec_register);
  */
 void cros_ec_unregister(struct cros_ec_device *ec_dev)
 {
+	if (ec_dev->mkbp_event_supported)
+		blocking_notifier_chain_unregister(&ec_dev->event_notifier,
+						   &ec_dev->notifier_ready);
 	platform_device_unregister(ec_dev->pd);
 	platform_device_unregister(ec_dev->ec);
 	mutex_destroy(&ec_dev->lock);
-- 
2.50.1