[PATCH] hw/scsi/ncr710: Fix null pointer dereference in `ncr710_transfer_data`

[zhaoguohan_salmon]

From: GuoHan Zhao <zhaoguo...@kylinos.cn>

Fix a null pointer dereference issue.

The code dereferences s->current before checking if it is NULL. Move the
null check before the dereference to prevent potential crashes.

This issue could occur if s->current is NULL when the function reaches
the "Host adapter (re)connected" path, though this should not normally
happen during correct operation.

Fixes: 9ce93b74cdc0 ("ncr710: Add driver for the NCR 53c710 SCSI chip")
Signed-off-by: GuoHan Zhao <zhaoguo...@kylinos.cn>
---
 hw/scsi/ncr53c710.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/hw/scsi/ncr53c710.c b/hw/scsi/ncr53c710.c
index ade951b1d107..e479a212bc54 100644
--- a/hw/scsi/ncr53c710.c
+++ b/hw/scsi/ncr53c710.c
@@ -831,14 +831,14 @@ void ncr710_transfer_data(SCSIRequest *req, uint32_t len)
         }
     }
 
-    /* Host adapter (re)connected */
-    s->current->dma_len = len;
-    s->command_complete = NCR710_CMD_DATA_READY;
-
     if (!s->current) {
         return;
     }
 
+    /* Host adapter (re)connected */
+    s->current->dma_len = len;
+    s->command_complete = NCR710_CMD_DATA_READY;
+
     if (s->waiting) {
         s->scntl1 |= NCR710_SCNTL1_CON;
         s->istat |= NCR710_ISTAT_CON;
-- 
2.43.0