From 3ff504908f95093cc013a01d1cafb1f7fda0ab34 Mon Sep 17 00:00:00 2001 From: Huazhong Tan Date: Tue, 1 May 2018 19:56:03 +0100 Subject: [PATCH] net: hns3: fix a dead loop in hclge_cmd_csq_clean 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 Signed-off-by: Peng Li Signed-off-by: Salil Mehta Signed-off-by: David S. Miller --- .../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 ff13d1876d9e..fab70683bbf7 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)); -- 2.45.2