Am 26.05.24 um 21:43 schrieb Sasha Levin:

This is a note to let you know that I've just added the patch titled

 platform/x86: xiaomi-wmi: Fix race condition when reporting key events

to the 6.6-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: platform-x86-xiaomi-wmi-fix-race-condition-when-repo.patch and it can be found in the queue-6.6 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.

Hi,

the underlying race condition can only be triggered since commit e2ffcda16290 ("ACPI: OSL: Allow Notify () handlers to run on all CPUs"), which afaik was introduced with kernel 6.8.

Because of this, i do not think that we have to backport this commit to kernels before 6.8.

Thanks, Armin Wolf

commit 831f943a69833152081ec7393af598f0c8b415fa Author: Armin Wolf W_Armin@gmx.de Date: Tue Apr 2 16:30:57 2024 +0200

 platform/x86: xiaomi-wmi: Fix race condition when reporting key events

 [ Upstream commit 290680c2da8061e410bcaec4b21584ed951479af ]

 Multiple WMI events can be received concurrently, so multiple instances
 of xiaomi_wmi_notify() can be active at the same time. Since the input
 device is shared between those handlers, the key input sequence can be
 disturbed.

 Fix this by protecting the key input sequence with a mutex.

 Compile-tested only.

 Fixes: edb73f4f0247 ("platform/x86: wmi: add Xiaomi WMI key driver")
 Signed-off-by: Armin Wolf <W_Armin@gmx.de>
 Link: https://lore.kernel.org/r/20240402143059.8456-2-W_Armin@gmx.de
 Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
 Reviewed-by: Hans de Goede <hdegoede@redhat.com>
 Signed-off-by: Hans de Goede <hdegoede@redhat.com>
 Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/platform/x86/xiaomi-wmi.c b/drivers/platform/x86/xiaomi-wmi.c index 54a2546bb93bf..be80f0bda9484 100644 --- a/drivers/platform/x86/xiaomi-wmi.c +++ b/drivers/platform/x86/xiaomi-wmi.c @@ -2,8 +2,10 @@ /* WMI driver for Xiaomi Laptops */

#include <linux/acpi.h> +#include <linux/device.h> #include <linux/input.h> #include <linux/module.h> +#include <linux/mutex.h> #include <linux/wmi.h>

#include <uapi/linux/input-event-codes.h> @@ -20,12 +22,21 @@

struct xiaomi_wmi { struct input_dev *input_dev;

• struct mutex key_lock; /* Protects the key event sequence */ unsigned int key_code; };

+static void xiaomi_mutex_destroy(void *data) +{

• struct mutex *lock = data;
• mutex_destroy(lock);

+}

• static int xiaomi_wmi_probe(struct wmi_device *wdev, const void *context) { struct xiaomi_wmi *data;

• int ret;

  if (wdev == NULL || context == NULL) return -EINVAL;

@@ -35,6 +46,11 @@ static int xiaomi_wmi_probe(struct wmi_device *wdev, const void *context) return -ENOMEM; dev_set_drvdata(&wdev->dev, data);

• mutex_init(&data->key_lock);
• ret = devm_add_action_or_reset(&wdev->dev, xiaomi_mutex_destroy, &data->key_lock);
• if (ret < 0)

• return ret;
  

• data->input_dev = devm_input_allocate_device(&wdev->dev); if (data->input_dev == NULL) return -ENOMEM;

@@ -59,10 +75,12 @@ static void xiaomi_wmi_notify(struct wmi_device *wdev, union acpi_object *dummy) if (data == NULL) return;

• mutex_lock(&data->key_lock); input_report_key(data->input_dev, data->key_code, 1); input_sync(data->input_dev); input_report_key(data->input_dev, data->key_code, 0); input_sync(data->input_dev);

• mutex_unlock(&data->key_lock); }

  static const struct wmi_device_id xiaomi_wmi_id_table[] = {