Commit 71f64283 authored by Andy Shevchenko's avatar Andy Shevchenko Committed by Rafael J. Wysocki
Browse files

ACPI: utils: Fix reference counting in for_each_acpi_dev_match() 



Currently it's possible to iterate over the dangling pointer in case the device
suddenly disappears. This may happen becase callers put it at the end of a loop.

Instead, let's move that call inside acpi_dev_get_next_match_dev().

Fixes: 803abec6 ("media: ipu3-cio2: Add cio2-bridge to ipu3-cio2 driver")
Fixes: bf263f64 ("media: ACPI / bus: Add acpi_dev_get_next_match_dev() and helper macro")
Fixes: edbd1bc4 ("efi/dev-path-parser: Switch to use for_each_acpi_dev_match()")
Signed-off-by: default avatarAndy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: default avatarDaniel Scally <djrscally@gmail.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 2734d6c1

drivers/acpi/utils.c

+3 −4
Original line number Diff line number Diff line
@@ -860,11 +860,9 @@ EXPORT_SYMBOL(acpi_dev_present); 
 * Return the next match of ACPI device if another matching device was present

 * at the moment of invocation, or NULL otherwise.

 *

 * FIXME: The function does not tolerate the sudden disappearance of @adev, e.g.

 * in the case of a hotplug event. That said, the caller should ensure that

 * this will never happen.

 *

 * The caller is responsible for invoking acpi_dev_put() on the returned device.

 * On the other hand the function invokes  acpi_dev_put() on the given @adev

 * assuming that its reference counter had been increased beforehand.

 *

 * See additional information in acpi_dev_present() as well.

 */
@@ -880,6 +878,7 @@ acpi_dev_get_next_match_dev(struct acpi_device *adev, const char *hid, const cha 
	match.hrv = hrv;



	dev = bus_find_device(&acpi_bus_type, start, &match, acpi_dev_match_cb);

	acpi_dev_put(adev);

	return dev ? to_acpi_device(dev) : NULL;

}

EXPORT_SYMBOL(acpi_dev_get_next_match_dev);

drivers/firmware/efi/dev-path-parser.c

+0 −1
Original line number Diff line number Diff line
@@ -34,7 +34,6 @@ static long __init parse_acpi_path(const struct efi_dev_path *node, 
			break;

		if (!adev->pnp.unique_id && node->acpi.uid == 0)

			break;

		acpi_dev_put(adev);

	}

	if (!adev)

		return -ENODEV;

drivers/media/pci/intel/ipu3/cio2-bridge.c

+2 −4
Original line number Diff line number Diff line
@@ -173,10 +173,8 @@ static int cio2_bridge_connect_sensor(const struct cio2_sensor_config *cfg, 
	int ret;



	for_each_acpi_dev_match(adev, cfg->hid, NULL, -1) {

		if (!adev->status.enabled) {

			acpi_dev_put(adev);

		if (!adev->status.enabled)

			continue;

		}



		if (bridge->n_sensors >= CIO2_NUM_PORTS) {

			acpi_dev_put(adev);
@@ -185,7 +183,6 @@ static int cio2_bridge_connect_sensor(const struct cio2_sensor_config *cfg, 
		}



		sensor = &bridge->sensors[bridge->n_sensors];

		sensor->adev = adev;

		strscpy(sensor->name, cfg->hid, sizeof(sensor->name));



		ret = cio2_bridge_read_acpi_buffer(adev, "SSDB",
@@ -215,6 +212,7 @@ static int cio2_bridge_connect_sensor(const struct cio2_sensor_config *cfg, 
			goto err_free_swnodes;

		}



		sensor->adev = acpi_dev_get(adev);

		adev->fwnode.secondary = fwnode;



		dev_info(&cio2->dev, "Found supported sensor %s\n",

include/acpi/acpi_bus.h

+0 −5
Original line number Diff line number Diff line
@@ -707,11 +707,6 @@ acpi_dev_get_first_match_dev(const char *hid, const char *uid, s64 hrv); 
 * @hrv: Hardware Revision of the device, pass -1 to not check _HRV

 *

 * The caller is responsible for invoking acpi_dev_put() on the returned device.

 *

 * FIXME: Due to above requirement there is a window that may invalidate @adev

 * and next iteration will use a dangling pointer, e.g. in the case of a

 * hotplug event. That said, the caller should ensure that this will never

 * happen.

 */

#define for_each_acpi_dev_match(adev, hid, uid, hrv)			\

	for (adev = acpi_dev_get_first_match_dev(hid, uid, hrv);	\