Affected: Alpaquita:23: linux-lts, Alpaquita:25: linux-lts, Alpaquita:stream: linux-lts

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.

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.

kernel-devel-7.2.8-1.1 on GA media

Affected: Ubuntu:16.04:LTS: linux-hwe-edge, Ubuntu:18.04:LTS: linux-aws-5.0, Ubuntu:18.04:LTS: linux-aws-5.3, Ubuntu:18.04:LTS: linux-azure, Ubuntu:18.04:LTS: linux-azure-5.3, Ubuntu:18.04:LTS: linux-azure-edge, Ubuntu:18.04:LTS: linux-gcp, Ubuntu:18.04:LTS: linux-gcp-5.3, Ubuntu:18.04:LTS: linux-gke-4.15, Ubuntu:18.04:LTS: linux-gke-5.4 and 154 more

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.