qlcnic: potential NULL dereference in qlcnic_83xx_get_minidump_template()

BugLink: https://bugs.launchpad.net/bugs/1878232

commit 5f46feab upstream.

If qlcnic_fw_cmd_get_minidump_temp() fails then "fw_dump->tmpl_hdr" is
NULL or possibly freed.  It can lead to an oops later.

Fixes: d01a6d3c ('qlcnic: Add support to enable capability to extend minidump for iSCSI')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ian May <ian.may@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

drivers/net/ethernet/qlogic/qlcnic/qlcnic_minidump.c

@@ -1419,6 +1419,7 @@ void qlcnic_83xx_get_minidump_template(struct qlcnic_adapter *adapter)
 	struct qlcnic_fw_dump *fw_dump = &ahw->fw_dump;
 	struct pci_dev *pdev = adapter->pdev;
 	bool extended = false;
+	int ret;
 
 	prev_version = adapter->fw_version;
 	current_version = qlcnic_83xx_get_fw_version(adapter);
@@ -1429,7 +1430,10 @@ void qlcnic_83xx_get_minidump_template(struct qlcnic_adapter *adapter)
 		if (qlcnic_83xx_md_check_extended_dump_capability(adapter))
 			extended = !qlcnic_83xx_extend_md_capab(adapter);
 
-		if (!qlcnic_fw_cmd_get_minidump_temp(adapter))
+		ret = qlcnic_fw_cmd_get_minidump_temp(adapter);
+		if (ret)
+			return;
+
 		dev_info(&pdev->dev, "Supports FW dump capability\n");
 
 		/* Once we have minidump template with extended iSCSI dump