From 095cfdf857a38972762d92379a848349fda00fe1 Mon Sep 17 00:00:00 2001 From: Hongbo Yao Date: Mon, 7 Jan 2019 10:22:07 +0800 Subject: nvme-pci: fix out of bounds access in nvme_cqe_pending [ Upstream commit dcca1662727220d18fa351097ddff33f95f516c5 ] There is an out of bounds array access in nvme_cqe_peding(). When enable irq_thread for nvme interrupt, there is racing between the nvmeq->cq_head updating and reading. nvmeq->cq_head is updated in nvme_update_cq_head(), if nvmeq->cq_head equals nvmeq->q_depth and before its value set to zero, nvme_cqe_pending() uses its value as an array index, the index will be out of bounds. Signed-off-by: Hongbo Yao [hch: slight coding style update] Signed-off-by: Christoph Hellwig Signed-off-by: Sasha Levin --- drivers/nvme/host/pci.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'drivers/nvme') diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c index 40f76b4f08fc..f46313f441ec 100644 --- a/drivers/nvme/host/pci.c +++ b/drivers/nvme/host/pci.c @@ -908,9 +908,11 @@ static void nvme_complete_cqes(struct nvme_queue *nvmeq, u16 start, u16 end) static inline void nvme_update_cq_head(struct nvme_queue *nvmeq) { - if (++nvmeq->cq_head == nvmeq->q_depth) { + if (nvmeq->cq_head == nvmeq->q_depth - 1) { nvmeq->cq_head = 0; nvmeq->cq_phase = !nvmeq->cq_phase; + } else { + nvmeq->cq_head++; } } -- cgit v1.2.3-55-g7522