From: Alexandra Diupina <adiupina@astralinux.ru>
Date: Fri, 28 Jul 2023 15:35:21 +0300
Subject: scsi: 53c700: Check that command slot is not NULL
Git-commit: 8366d1f1249a0d0bba41d0bd1298d63e5d34c7f7
Patch-mainline: v6.5-rc6
References: git-fixes

Add a check for the command slot value to avoid dereferencing a NULL
pointer.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Co-developed-by: Vladimir Telezhnikov <vtelezhnikov@astralinux.ru>
Signed-off-by: Vladimir Telezhnikov <vtelezhnikov@astralinux.ru>
Signed-off-by: Alexandra Diupina <adiupina@astralinux.ru>
Link: https://lore.kernel.org/r/20230728123521.18293-1-adiupina@astralinux.ru
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Lee Duncan <lduncan@suse.com>
---
 drivers/scsi/53c700.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/53c700.c b/drivers/scsi/53c700.c
index e1e4f9d10887..857be0f3ae5b 100644
--- a/drivers/scsi/53c700.c
+++ b/drivers/scsi/53c700.c
@@ -1598,7 +1598,7 @@ NCR_700_intr(int irq, void *dev_id)
 				printk("scsi%d (%d:%d) PHASE MISMATCH IN SEND MESSAGE %d remain, return %p[%04x], phase %s\n", host->host_no, pun, lun, count, (void *)temp, temp - hostdata->pScript, sbcl_to_string(NCR_700_readb(host, SBCL_REG)));
 #endif
 				resume_offset = hostdata->pScript + Ent_SendMessagePhaseMismatch;
-			} else if(dsp >= to32bit(&slot->pSG[0].ins) &&
+			} else if (slot && dsp >= to32bit(&slot->pSG[0].ins) &&
 				  dsp <= to32bit(&slot->pSG[NCR_700_SG_SEGMENTS].ins)) {
 				int data_transfer = NCR_700_readl(host, DBC_REG) & 0xffffff;
 				int SGcount = (dsp - to32bit(&slot->pSG[0].ins))/sizeof(struct NCR_700_SG_List);