firmware_loader: Fix use-after-free during unregister

In the following code within firmware_upload_unregister(), the call to
device_unregister() could result in the dev_release function freeing the
fw_upload_priv structure before it is dereferenced for the call to
module_put(). This bug was found by the kernel test robot using
CONFIG_KASAN while running the firmware selftests.

  device_unregister(&fw_sysfs->dev);
  module_put(fw_upload_priv->module);

The problem is fixed by copying fw_upload_priv->module to a local variable
for use when calling device_unregister().

Fixes: 97730bbb242c ("firmware_loader: Add firmware-upload support")
Cc: stable <[email protected]>
Reported-by: kernel test robot <[email protected]>
Reviewed-by: Matthew Gerlach <[email protected]>
Signed-off-by: Russ Weight <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

0 files changed, 0 insertions, 0 deletions