mei: bus: fix unlink on bus in error path

commit a43866856125c3c432e2fbb6cc63cee1539ec4a7 upstream.

Unconditional call to mei_cl_unlink in mei_cl_bus_dev_release leads
to call of the mei_cl_unlink without corresponding mei_cl_link.
This leads to miscalculation of open_handle_count (decrease without
increase).

Call unlink in mei_cldev_enable fail path and remove blanket unlink
from mei_cl_bus_dev_release.

Fixes: 34f1166afd67 ("mei: bus: need to unlink client before freeing")
Cc: <stable@vger.kernel.org>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Reviewed-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Link: https://lore.kernel.org/r/20221212220247.286019-1-tomas.winkler@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/misc/mei/bus.c b/drivers/misc/mei/bus.c
index 46aa355..7b7f419 100644 (file)
--- a/drivers/misc/mei/bus.c
+++ b/drivers/misc/mei/bus.c
@@ -665,13 +665,15 @@ void *mei_cldev_dma_map(struct mei_cl_device *cldev, u8 buffer_id, size_t size)
        if (cl->state == MEI_FILE_UNINITIALIZED) {
                ret = mei_cl_link(cl);
                if (ret)
-                       goto out;
+                       goto notlinked;
                /* update pointers */
                cl->cldev = cldev;
        }
 
        ret = mei_cl_dma_alloc_and_map(cl, NULL, buffer_id, size);
-out:
+       if (ret)
+               mei_cl_unlink(cl);
+notlinked:
        mutex_unlock(&bus->device_lock);
        if (ret)
                return ERR_PTR(ret);
@@ -721,7 +723,7 @@ int mei_cldev_enable(struct mei_cl_device *cldev)
        if (cl->state == MEI_FILE_UNINITIALIZED) {
                ret = mei_cl_link(cl);
                if (ret)
-                       goto out;
+                       goto notlinked;
                /* update pointers */
                cl->cldev = cldev;
        }
@@ -748,6 +750,9 @@ int mei_cldev_enable(struct mei_cl_device *cldev)
        }
 
 out:
+       if (ret)
+               mei_cl_unlink(cl);
+notlinked:
        mutex_unlock(&bus->device_lock);
 
        return ret;
@@ -1115,7 +1120,6 @@ static void mei_cl_bus_dev_release(struct device *dev)
        mei_cl_flush_queues(cldev->cl, NULL);
        mei_me_cl_put(cldev->me_cl);
        mei_dev_bus_put(cldev->bus);
-       mei_cl_unlink(cldev->cl);
        kfree(cldev->cl);
        kfree(cldev);
 }