In the Linux kernel, the following vulnerability has been resolved:
RDMA/erdma: Fix CEQ tasklet use-after-free on removal
Each CEQ interrupt handler only schedules eqc->tasklet. The tasklet calls
erdma_ceq_completion_handler(), which reads the DMA-coherent EQ ring
through get_next_valid_eqe() and updates eq->dbrec through notify_eq().
erdma_ceqs_uninit() frees each CEQ IRQ and then destroys its EQ.
free_irq() prevents another hard IRQ and waits for an in-flight handler,
but it does not drain a tasklet that the handler already scheduled. The
tasklet can therefore access eq->qbuf or eq->dbrec after
erdma_eq_destroy() frees them.
Clearing ceq_cb->ready does not synchronize with a tasklet that already
passed the check at the start of erdma_ceq_completion_handler().
Kill the tasklet after free_irq(), when no handler can schedule it again,
and before erdma_ceq_uninit_one() releases the EQ buffers.
