4.20-stable review patch. If anyone has any objections, please let me know.
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From: Rafael J. Wysocki rafael.j.wysocki@intel.com
commit e121a833745b4708b660e3fe6776129c2956b041 upstream.
__device_release_driver() has to check dev->bus->need_parent_lock before dropping the parent lock and acquiring it again as it may attempt to drop a lock that hasn't been acquired or lock a device that shouldn't be locked and create a lock imbalance.
Fixes: 8c97a46af04b (driver core: hold dev's parent lock when needed) Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Cc: stable stable@vger.kernel.org Reviewed-by: Daniel Vetter daniel.vetter@ffwll.ch Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/base/dd.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -933,11 +933,11 @@ static void __device_release_driver(stru
while (device_links_busy(dev)) { device_unlock(dev); - if (parent) + if (parent && dev->bus->need_parent_lock) device_unlock(parent);
device_links_unbind_consumers(dev); - if (parent) + if (parent && dev->bus->need_parent_lock) device_lock(parent);
device_lock(dev);