From e3fd112cbf21d049faf64ba1471d72b93c22109a Mon Sep 17 00:00:00 2001 From: "Kalderon, Michal" Date: Mon, 5 Mar 2018 10:50:10 +0200 Subject: [PATCH] RDMA/qedr: Fix kernel panic when running fio over NFSoRDMA Race in qedr_poll_cq, lastest_cqe wasn't protected by lock, leading to a case where two context's accessing poll_cq at the same time lead to one of them having a pointer to an old latest_cqe and reading an invalid cqe element Signed-off-by: Amit Radzi Signed-off-by: Michal Kalderon Signed-off-by: Ariel Elior Signed-off-by: Jason Gunthorpe --- drivers/infiniband/hw/qedr/verbs.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/infiniband/hw/qedr/verbs.c b/drivers/infiniband/hw/qedr/verbs.c index 53f00dbf313f..102b9e0efe9a 100644 --- a/drivers/infiniband/hw/qedr/verbs.c +++ b/drivers/infiniband/hw/qedr/verbs.c @@ -3724,7 +3724,7 @@ int qedr_poll_cq(struct ib_cq *ibcq, int num_entries, struct ib_wc *wc) { struct qedr_dev *dev = get_qedr_dev(ibcq->device); struct qedr_cq *cq = get_qedr_cq(ibcq); - union rdma_cqe *cqe = cq->latest_cqe; + union rdma_cqe *cqe; u32 old_cons, new_cons; unsigned long flags; int update = 0; @@ -3741,6 +3741,7 @@ int qedr_poll_cq(struct ib_cq *ibcq, int num_entries, struct ib_wc *wc) return qedr_gsi_poll_cq(ibcq, num_entries, wc); spin_lock_irqsave(&cq->cq_lock, flags); + cqe = cq->latest_cqe; old_cons = qed_chain_get_cons_idx_u32(&cq->pbl); while (num_entries && is_valid_cqe(cq, cqe)) { struct qedr_qp *qp; -- 2.30.2