In the Linux kernel, the following vulnerability has been resolved:

padata: avoid UAF for reorder_work

Although the previous patch can avoid ps and ps UAF for _do_serial, it
can not avoid potential UAF issue for reorder_work. This issue can
happen just as below:

crypto_request			crypto_request		crypto_del_alg
padata_do_serial
  ...
  padata_reorder
    // processes all remaining
    // requests then breaks
    while (1) {
      if (!padata)
        break;
      ...
    }

				padata_do_serial
				  // new request added
				  list_add
    // sees the new request
    queue_work(reorder_work)
				  padata_reorder
				    queue_work_on(squeue->work)
...

				<kworker context>
				padata_serial_worker
				// completes new request,
				// no more outstanding
				// requests

							crypto_del_alg
							  // free pd

<kworker context>
invoke_padata_reorder
  // UAF of pd

To avoid UAF for 'reorder_work', get 'pd' ref before put 'reorder_work'
into the 'serial_wq' and put 'pd' ref until the 'serial_wq' finish.

https://git.kernel.org/stable/c/6f45ef616775b0ce7889b0f6077fc8d681ab30bc

https://git.kernel.org/stable/c/7000507bb0d2ceb545c0a690e0c707c897d102c2

https://git.kernel.org/stable/c/8ca38d0ca8c3d30dd18d311f1a7ec5cb56972cac

https://git.kernel.org/stable/c/a54091c24220a4cd847d5b4f36d678edacddbaf0

https://git.kernel.org/stable/c/dd7d37ccf6b11f3d95e797ebe4e9e886d0332600