In the Linux kernel, the following vulnerability has been resolved:
dmaengine: idxd: fix fdev setup failure cleanup in idxd_cdev_open()
The failed_dev_add and failed_dev_name paths drop the file-device reference while wq->wq_lock is still held. If put_device(fdev) drops the last reference, idxd_file_dev_release() runs synchronously and tries to take wq->wq_lock again, deadlocking.
Those paths also fall through into the later ctx cleanup labels even though idxd_file_dev_release() owns that cleanup and frees ctx. This can make idxd_xa_pasid_remove(ctx) and kfree(ctx) operate on a freed context.
Move idxd_wq_get() before file-device setup can fail, since the release callback always calls idxd_wq_put(). Then unlock wq->wq_lock before put_device(fdev) and return directly from the file-device setup failure path, leaving ctx cleanup to the release callback.
References
- https://git.kernel.org/stable/c/0679c0c189d2548f00e1bac95be28e2df5c6c7f7
- https://git.kernel.org/stable/c/6e26a41c4c1a706edaaa7c7dffc6b3b945707a55
- https://git.kernel.org/stable/c/778ccbded2c8749c5be7f0dfa04fc9977a36fb7e
- https://git.kernel.org/stable/c/8d5d28285728be47c82fdf1c48be4268293c90e7
- https://git.kernel.org/stable/c/ee1d7274102285d78a53161fc705a8d8cd40b066