In the Linux kernel, the following vulnerability has been resolved:
block, bfq: fix uaf for bfqq in bfq_exit_icq_bfqq
Commit 64dc8c732f5c (block, bfq: fix possible uaf for bfqq->bic) will access bic->bfqq in bic_set_bfqq(), however, bfq_exit_icq_bfqq() can free bfqq first, and then call bic_set_bfqq(), which will cause uaf.
Fix the problem by moving bfq_exit_bfqq() behind bic_set_bfqq().