[PATCH v2] drm/i915/dsi: fix i2c adapter reference leak in i2c_adapter_lookup()

[PATCH v2] drm/i915/dsi: fix i2c adapter reference leak in i2c_adapter_lookup()

[Ma Ke]

i2c_adapter_lookup() acquires a reference on the i2c adapter through
i2c_acpi_find_adapter_by_handle() but not releases it.  Each
invocation of this ACPI resource callback leaks one device reference,
potentially leading to resource exhaustion over repeated driver
load/unload cycles.

Calling path: i2c_acpi_find_adapter_by_handle() -> bus_find_device()
-> get_device.

Found by code review.

Signed-off-by: Ma Ke <make_ruc2021@163.com>
Cc: stable@vger.kernel.org
Fixes: 8cbf89db2941 ("drm/i915/dsi: Parse the I2C element from the VBT MIPI sequence block (v3)")
---
Changes in v2:
- Changed email to trigger CI, no code change.
---
 drivers/gpu/drm/i915/display/intel_dsi_vbt.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dsi_vbt.c b/drivers/gpu/drm/i915/display/intel_dsi_vbt.c
index fe12041e913c..2097c5d17cb7 100644
--- a/drivers/gpu/drm/i915/display/intel_dsi_vbt.c
+++ b/drivers/gpu/drm/i915/display/intel_dsi_vbt.c
@@ -460,8 +460,10 @@ static int i2c_adapter_lookup(struct acpi_resource *ares, void *data)
 		return 1;
 
 	adapter = i2c_acpi_find_adapter_by_handle(adapter_handle);
-	if (adapter)
+	if (adapter) {
 		intel_dsi->i2c_bus_num = adapter->nr;
+		put_device(&adapter->dev);
+	}
 
 	return 1;
 }
-- 
2.43.0

Re: [PATCH v2] drm/i915/dsi: fix i2c adapter reference leak in i2c_adapter_lookup()

[Jani Nikula]

On Thu, 18 Jun 2026, Ma Ke <make_ruc2021@163.com> wrote:
> i2c_adapter_lookup() acquires a reference on the i2c adapter through
> i2c_acpi_find_adapter_by_handle() but not releases it.  Each
> invocation of this ACPI resource callback leaks one device reference,
> potentially leading to resource exhaustion over repeated driver
> load/unload cycles.
>
> Calling path: i2c_acpi_find_adapter_by_handle() -> bus_find_device()
> -> get_device.
>
> Found by code review.
>
> Signed-off-by: Ma Ke <make_ruc2021@163.com>
> Cc: stable@vger.kernel.org
> Fixes: 8cbf89db2941 ("drm/i915/dsi: Parse the I2C element from the VBT MIPI sequence block (v3)")
> ---
> Changes in v2:
> - Changed email to trigger CI, no code change.

Sorry, that won't do anything. Please just let us deal with it. :)

BR,
Jani.

> ---
>  drivers/gpu/drm/i915/display/intel_dsi_vbt.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dsi_vbt.c b/drivers/gpu/drm/i915/display/intel_dsi_vbt.c
> index fe12041e913c..2097c5d17cb7 100644
> --- a/drivers/gpu/drm/i915/display/intel_dsi_vbt.c
> +++ b/drivers/gpu/drm/i915/display/intel_dsi_vbt.c
> @@ -460,8 +460,10 @@ static int i2c_adapter_lookup(struct acpi_resource *ares, void *data)
>  		return 1;
>  
>  	adapter = i2c_acpi_find_adapter_by_handle(adapter_handle);
> -	if (adapter)
> +	if (adapter) {
>  		intel_dsi->i2c_bus_num = adapter->nr;
> +		put_device(&adapter->dev);
> +	}
>  
>  	return 1;
>  }

-- 
Jani Nikula, Intel