4.20-stable review patch. If anyone has any objections, please let me know.
------------------
[ 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 <yaohongbo@xxxxxxxxxx>
[hch: slight coding style update]
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/nvme/host/pci.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 0f45868e8af9..47597046c14f 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -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++;
}
}
--
2.19.1
