FAILED: patch "[PATCH] Bluetooth: btqcomsmd: destroy RPMsg endpoints before freeing" failed to apply to 6.6-stable tree

The patch below does not apply to the 6.6-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 <[email protected]>.

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-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x f5a427b16e45210dee656b0860728f3d496dee85
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026091650-java-skiing-cc15@gregkh' --subject-prefix 'PATCH 6.6.y' 'HEAD^..'

Possible dependencies:

thanks,

greg k-h

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

From f5a427b16e45210dee656b0860728f3d496dee85 Mon Sep 17 00:00:00 2001
From: Xu Rao <[email protected]>
Date: Fri, 4 Sep 2026 10:54:57 +0800
Subject: [PATCH] Bluetooth: btqcomsmd: destroy RPMsg endpoints before freeing
hci_dev

The command and ACL RPMsg endpoints store struct btqcomsmd as their callback private data. The receive callbacks dereference btq->hdev without taking an hci_dev reference.

The current teardown order frees the hci_dev before destroying the RPMsg endpoints in both the hci_register_dev() error path and the driver remove path. If WCNSS delivers data in that window, the endpoint callback can run with an already freed hci_dev and pass it to the Bluetooth core.

For qcom_smd endpoints, rpmsg_destroy_ept() closes the channel and clears the callback under the channel recv_lock. The receive path holds the same lock while invoking the callback, so destroying the endpoints first both prevents new callbacks and serializes with any callback already running.

Destroy the command and ACL endpoints before hci_free_dev(). Keep hci_unregister_dev() first during remove so the HCI core stops issuing operations before the transport endpoints are shut down. In the full registration-error cleanup path, return directly after freeing the hci_dev to avoid falling through to the partial-construction labels and destroying the endpoints twice.

index d2e13fcb6bab..d669ea4eb3eb 100644
@@ -188,7 +188,10 @@ static int btqcomsmd_probe(struct platform_device *pdev)
 	return 0;
 
 hci_free_dev:
+	rpmsg_destroy_ept(btq->cmd_channel);
+	rpmsg_destroy_ept(btq->acl_channel);
 	hci_free_dev(hdev);
+	return ret;
 destroy_cmd_channel:
 	rpmsg_destroy_ept(btq->cmd_channel);
 destroy_acl_channel:

@@ -202,10 +205,11 @@ static void btqcomsmd_remove(struct platform_device *pdev)
 	struct btqcomsmd *btq = platform_get_drvdata(pdev);
 
 	hci_unregister_dev(btq->hdev);
-	hci_free_dev(btq->hdev);
 
 	rpmsg_destroy_ept(btq->cmd_channel);
 	rpmsg_destroy_ept(btq->acl_channel);
+
+	hci_free_dev(btq->hdev);
 }
 
 static const struct of_device_id btqcomsmd_of_match[] = {

From: Uwe Kleine-König <[email protected]>

[ Upstream commit 4a62832f565c950d645a4f7b199a0a7985815940 ]

The .remove() callback for a platform driver returns an int which makes many driver authors wrongly assume it's possible to do error handling by returning an error code. However the value returned is ignored (apart from emitting a warning) and this typically results in resource leaks.

To improve here there is a quest to make the remove callback return void. In the first step of this quest all drivers are converted to .remove_new(), which already returns void. Eventually after all drivers are converted, .remove_new() will be renamed to .remove().

Trivially convert this driver from always returning zero in the remove callback to the void returning variant.

Stable-dep-of: f5a427b16e45 ("Bluetooth: btqcomsmd: destroy RPMsg endpoints before freeing hci_dev")

---
 drivers/bluetooth/btqcomsmd.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

index 11c7e04bf3947..88dbb2f3fabf9 100644
@@ -197,7 +197,7 @@ static int btqcomsmd_probe(struct platform_device *pdev)
 	return ret;
 }
 
-static int btqcomsmd_remove(struct platform_device *pdev)
+static void btqcomsmd_remove(struct platform_device *pdev)
 {
 	struct btqcomsmd *btq = platform_get_drvdata(pdev);
 

@@ -206,8 +206,6 @@ static int btqcomsmd_remove(struct platform_device *pdev)
 
 	rpmsg_destroy_ept(btq->cmd_channel);
 	rpmsg_destroy_ept(btq->acl_channel);
-
-	return 0;
 }
 
 static const struct of_device_id btqcomsmd_of_match[] = {

@@ -218,7 +216,7 @@ MODULE_DEVICE_TABLE(of, btqcomsmd_of_match);
 
 static struct platform_driver btqcomsmd_driver = {
 	.probe = btqcomsmd_probe,
-	.remove = btqcomsmd_remove,
+	.remove_new = btqcomsmd_remove,
 	.driver  = {
 		.name  = "btqcomsmd",
 		.of_match_table = btqcomsmd_of_match,

2.53.0

From: Xu Rao <[email protected]>

[ Upstream commit f5a427b16e45210dee656b0860728f3d496dee85 ]

The command and ACL RPMsg endpoints store struct btqcomsmd as their callback private data. The receive callbacks dereference btq->hdev without taking an hci_dev reference.

The current teardown order frees the hci_dev before destroying the RPMsg endpoints in both the hci_register_dev() error path and the driver remove path. If WCNSS delivers data in that window, the endpoint callback can run with an already freed hci_dev and pass it to the Bluetooth core.

For qcom_smd endpoints, rpmsg_destroy_ept() closes the channel and clears the callback under the channel recv_lock. The receive path holds the same lock while invoking the callback, so destroying the endpoints first both prevents new callbacks and serializes with any callback already running.

Destroy the command and ACL endpoints before hci_free_dev(). Keep hci_unregister_dev() first during remove so the HCI core stops issuing operations before the transport endpoints are shut down. In the full registration-error cleanup path, return directly after freeing the hci_dev to avoid falling through to the partial-construction labels and destroying the endpoints twice.

---
 drivers/bluetooth/btqcomsmd.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

index 88dbb2f3fabf9..4ce8354ebb86b 100644
@@ -188,7 +188,10 @@ static int btqcomsmd_probe(struct platform_device *pdev)
 	return 0;
 
 hci_free_dev:
+	rpmsg_destroy_ept(btq->cmd_channel);
+	rpmsg_destroy_ept(btq->acl_channel);
 	hci_free_dev(hdev);
+	return ret;
 destroy_cmd_channel:
 	rpmsg_destroy_ept(btq->cmd_channel);
 destroy_acl_channel:

@@ -202,10 +205,11 @@ static void btqcomsmd_remove(struct platform_device *pdev)
 	struct btqcomsmd *btq = platform_get_drvdata(pdev);
 
 	hci_unregister_dev(btq->hdev);
-	hci_free_dev(btq->hdev);
 
 	rpmsg_destroy_ept(btq->cmd_channel);
 	rpmsg_destroy_ept(btq->acl_channel);
+
+	hci_free_dev(btq->hdev);
 }
 
 static const struct of_device_id btqcomsmd_of_match[] = {

2.53.0