Commit c4a6f6e7 authored by Hongbo Yao's avatar Hongbo Yao Committed by Greg Kroah-Hartman

nvme-pci: fix out of bounds access in nvme_cqe_pending

[ Upstream commit dcca1662 ]

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: default avatarHongbo Yao <yaohongbo@huawei.com>
[hch: slight coding style update]
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent e0b9c207
......@@ -913,9 +913,11 @@ 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++;
}
}
......
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