linux-kernel - [char-misc-next] mei: bus: fix device leak

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Message-ID: <20250624071521.1281436-1-alexander.usyskin@intel.com>
Date: Tue, 24 Jun 2025 10:15:21 +0300
From: Alexander Usyskin <alexander.usyskin@...el.com>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: Reuven Abliyev <reuven.abliyev@...el.com>,
	Alexander Usyskin <alexander.usyskin@...el.com>,
	linux-kernel@...r.kernel.org
Subject: [char-misc-next] mei: bus: fix device leak

The bus rescan function creates bus devices for all clients.
The fixup routine is executed on all devices, unneeded
devices are removed and fully initialized once set
is_added flag to 1.

If link to firmware is reset right after all devices are
initialized, but before fixup is executed, the rescan tries
to remove devices.
The is_added flag is not set and the mei_cl_bus_dev_destroy
returns prematurely.
Allow to clean up device when is_added flag is unset to
account for above scenario.

Signed-off-by: Alexander Usyskin <alexander.usyskin@...el.com>
---
 drivers/misc/mei/bus.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/drivers/misc/mei/bus.c b/drivers/misc/mei/bus.c
index 67176caf5416..f2e5d550c6b4 100644
--- a/drivers/misc/mei/bus.c
+++ b/drivers/misc/mei/bus.c
@@ -1430,17 +1430,14 @@ static void mei_cl_bus_dev_stop(struct mei_cl_device *cldev)
  */
 static void mei_cl_bus_dev_destroy(struct mei_cl_device *cldev)
 {
-
 	WARN_ON(!mutex_is_locked(&cldev->bus->cl_bus_lock));
 
-	if (!cldev->is_added)
-		return;
-
-	device_del(&cldev->dev);
+	if (cldev->is_added) {
+		device_del(&cldev->dev);
+		cldev->is_added = 0;
+	}
 
 	list_del_init(&cldev->bus_list);
-
-	cldev->is_added = 0;
 	put_device(&cldev->dev);
 }
 
-- 
2.43.0