[PATCH net-next 7/9] net: hns3: fix a dead loop in hclge_cmd_csq_clean
From: Salil Mehta
Date: Tue May 01 2018 - 15:00:27 EST
From: Huazhong Tan <tanhuazhong@xxxxxxxxxx>
If head has invlid value then a dead loop can be triggered in
hclge_cmd_csq_clean. This patch adds sanity check for this case.
Fixes: 68c0a5c70614 ("net: hns3: Add HNS3 IMP(Integrated Mgmt Proc) Cmd
Interface Support")
Signed-off-by: Huazhong Tan <tanhuazhong@xxxxxxxxxx>
Signed-off-by: Peng Li <lipeng321@xxxxxxxxxx>
Signed-off-by: Salil Mehta <salil.mehta@xxxxxxxxxx>
---
.../net/ethernet/hisilicon/hns3/hns3pf/hclge_cmd.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_cmd.c b/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_cmd.c
index ff13d18..fab7068 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_cmd.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_cmd.c
@@ -31,6 +31,17 @@ static int hclge_ring_space(struct hclge_cmq_ring *ring)
return ring->desc_num - used - 1;
}
+static int is_valid_csq_clean_head(struct hclge_cmq_ring *ring, int h)
+{
+ int u = ring->next_to_use;
+ int c = ring->next_to_clean;
+
+ if (unlikely(h >= ring->desc_num))
+ return 0;
+
+ return u > c ? (h > c && h <= u) : (h > c || h <= u);
+}
+
static int hclge_alloc_cmd_desc(struct hclge_cmq_ring *ring)
{
int size = ring->desc_num * sizeof(struct hclge_desc);
@@ -141,6 +152,7 @@ static void hclge_cmd_init_regs(struct hclge_hw *hw)
static int hclge_cmd_csq_clean(struct hclge_hw *hw)
{
+ struct hclge_dev *hdev = (struct hclge_dev *)hw->back;
struct hclge_cmq_ring *csq = &hw->cmq.csq;
u16 ntc = csq->next_to_clean;
struct hclge_desc *desc;
@@ -149,6 +161,13 @@ static int hclge_cmd_csq_clean(struct hclge_hw *hw)
desc = &csq->desc[ntc];
head = hclge_read_dev(hw, HCLGE_NIC_CSQ_HEAD_REG);
+ rmb(); /* Make sure head is ready before touch any data */
+
+ if (!is_valid_csq_clean_head(csq, head)) {
+ dev_warn(&hdev->pdev->dev, "wrong head (%d, %d-%d)\n", head,
+ csq->next_to_use, csq->next_to_clean);
+ return 0;
+ }
while (head != ntc) {
memset(desc, 0, sizeof(*desc));
--
2.7.4