The 'slot' variable allows a NULL value. It is necessary to add a check for a null value to avoid dereferencing the null pointer. Found by Linux Verification Center (linuxtesting.org) with SVACE. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Co-developed-by: Vladimir Telezhnikov <vtelezhnikov@xxxxxxxxxxxxx> Signed-off-by: Vladimir Telezhnikov <vtelezhnikov@xxxxxxxxxxxxx> Signed-off-by: Alexandra Diupina <adiupina@xxxxxxxxxxxxx> --- drivers/scsi/53c700.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/scsi/53c700.c b/drivers/scsi/53c700.c index e1e4f9d10887..8e5468d1733d 100644 --- a/drivers/scsi/53c700.c +++ b/drivers/scsi/53c700.c @@ -1598,6 +1598,8 @@ 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 (!slot) { + printk(KERN_ERR "53c700: SCSI DONE HAS NULL SCp\n"); } else if(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; -- 2.30.2