[PATCH] Bluetooth: btmtksdio: fix usage_count leak when autosuspend_delay is negative

[PATCH] Bluetooth: btmtksdio: fix usage_count leak when autosuspend_delay is negative

[Guangshuo Li]

btmtksdio_setup() calls pm_runtime_use_autosuspend() when runtime PM
is supported, but btmtksdio_remove() does not call the matching
pm_runtime_dont_use_autosuspend() when removing the device.

If the autosuspend delay is set to a negative value while autosuspend
is enabled, the runtime PM core increments usage_count to prevent
runtime suspend. Without calling pm_runtime_dont_use_autosuspend()
during driver teardown, this reference is not dropped and usage_count
remains unbalanced.

Add the missing pm_runtime_dont_use_autosuspend() call in the remove
path before restoring the runtime PM usage reference.

This issue was found by manual code inspection.

Fixes: 7f3c563c575e ("Bluetooth: btmtksdio: Add runtime PM support to SDIO based Bluetooth")
Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
---
 drivers/bluetooth/btmtksdio.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/bluetooth/btmtksdio.c b/drivers/bluetooth/btmtksdio.c
index c6f80c419e90..4e1012e90979 100644
--- a/drivers/bluetooth/btmtksdio.c
+++ b/drivers/bluetooth/btmtksdio.c
@@ -1480,6 +1480,9 @@ static void btmtksdio_remove(struct sdio_func *func)
 	if (test_bit(BTMTKSDIO_FUNC_ENABLED, &bdev->tx_state))
 		btmtksdio_close(hdev);
 
+	if (bdev->data->pm_runtime_supported)
+		pm_runtime_dont_use_autosuspend(bdev->dev);
+
 	/* Be consistent the state in btmtksdio_probe */
 	pm_runtime_get_noresume(bdev->dev);
 
-- 
2.43.0

Re: [PATCH] Bluetooth: btmtksdio: fix usage_count leak when autosuspend_delay is negative

[patchwork-bot+bluetooth]

Hello:

This patch was applied to bluetooth/bluetooth-next.git (master)
by Luiz Augusto von Dentz <luiz.von.dentz@intel.com>:

On Fri,  7 Aug 2026 23:14:47 +0800 you wrote:
> btmtksdio_setup() calls pm_runtime_use_autosuspend() when runtime PM
> is supported, but btmtksdio_remove() does not call the matching
> pm_runtime_dont_use_autosuspend() when removing the device.
> 
> If the autosuspend delay is set to a negative value while autosuspend
> is enabled, the runtime PM core increments usage_count to prevent
> runtime suspend. Without calling pm_runtime_dont_use_autosuspend()
> during driver teardown, this reference is not dropped and usage_count
> remains unbalanced.
> 
> [...]

Here is the summary with links:
  - Bluetooth: btmtksdio: fix usage_count leak when autosuspend_delay is negative
    https://git.kernel.org/bluetooth/bluetooth-next/c/1e4acc44552b

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
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Re: [PATCH] Bluetooth: btmtksdio: fix usage_count leak when autosuspend_delay is negative

[Johan Hovold]

On Fri, Aug 07, 2026 at 11:14:47PM +0800, Guangshuo Li wrote:
> btmtksdio_setup() calls pm_runtime_use_autosuspend() when runtime PM
> is supported, but btmtksdio_remove() does not call the matching
> pm_runtime_dont_use_autosuspend() when removing the device.
> 
> If the autosuspend delay is set to a negative value while autosuspend
> is enabled, the runtime PM core increments usage_count to prevent
> runtime suspend. Without calling pm_runtime_dont_use_autosuspend()
> during driver teardown, this reference is not dropped and usage_count
> remains unbalanced.

I noticed the bluetooth ones have already been picked up, but for the
record:

As I've explained elsewhere, this is just misleading. There is no usage
count leak here as the count is balanced whenever the user re-enables
autosuspend through sysfs (by writing a non-negative timeout).

Drivers should clean up after themselves and disable autosuspend, but
this is more of a clean up than a fix and should not be backported.

You've sent upwards of 60 of these in the matter of a just a few days,
some which have even been picked up. Please send follow-ups (replies or
v2s) as soon as possible to prevent further of these from getting
merged.

> Add the missing pm_runtime_dont_use_autosuspend() call in the remove
> path before restoring the runtime PM usage reference.
> 
> This issue was found by manual code inspection.
> 
> Fixes: 7f3c563c575e ("Bluetooth: btmtksdio: Add runtime PM support to SDIO based Bluetooth")
> Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
> ---
>  drivers/bluetooth/btmtksdio.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/bluetooth/btmtksdio.c b/drivers/bluetooth/btmtksdio.c
> index c6f80c419e90..4e1012e90979 100644
> --- a/drivers/bluetooth/btmtksdio.c
> +++ b/drivers/bluetooth/btmtksdio.c
> @@ -1480,6 +1480,9 @@ static void btmtksdio_remove(struct sdio_func *func)
>  	if (test_bit(BTMTKSDIO_FUNC_ENABLED, &bdev->tx_state))
>  		btmtksdio_close(hdev);
>  
> +	if (bdev->data->pm_runtime_supported)
> +		pm_runtime_dont_use_autosuspend(bdev->dev);
> +
>  	/* Be consistent the state in btmtksdio_probe */
>  	pm_runtime_get_noresume(bdev->dev);

Johan