net: hns3: fix the exception when query imp info

mainline inclusion
from mainline-v5.15-rc2
commit 472430a7
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I4CVS3
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=472430a7b066

----------------------------------------------------------------------

When the command for querying imp info is issued to the firmware,
if the firmware does not support the command, the returned value
of bd num is 0.
Add protection mechanism before alloc memory to prevent apply for
0-length memory.

Fixes: 0b198b0d ("net: hns3: refactor dump m7 info of debugfs")
Signed-off-by: Jiaran Zhang <zhangjiaran@huawei.com>
Signed-off-by: NGuangbin Huang <huangguangbin2@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Reviewed-by: NYongxin Li <liyongxin1@huawei.com>
Signed-off-by: NJunxin Chen <chenjunxin1@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_debugfs.c

@@ -1724,6 +1724,10 @@ hclge_dbg_get_imp_stats_info(struct hclge_dev *hdev, char *buf, int len)
 	}
 
 	bd_num = le32_to_cpu(req->bd_num);
+	if (!bd_num) {
+		dev_err(&hdev->pdev->dev, "imp statistics bd number is 0!\n");
+		return -EINVAL;
+	}
 
 	desc_src = kcalloc(bd_num, sizeof(struct hclge_desc), GFP_KERNEL);
 	if (!desc_src)