[PATCH 4.4 039/159] scsi: sym53c8xx: fix NULL pointer dereference panic in sym_int_sir()

[Greg Kroah-Hartman]

From: George Kennedy <george.kennedy@xxxxxxxxxx>

[ Upstream commit 288315e95264b6355e26609e9dec5dc4563d4ab0 ]

sym_int_sir() in sym_hipd.c does not check the command pointer for NULL before
using it in debug message prints.

Suggested-by: Matthew Wilcox <matthew.wilcox@xxxxxxxxxx>
Signed-off-by: George Kennedy <george.kennedy@xxxxxxxxxx>
Reviewed-by: Mark Kanda <mark.kanda@xxxxxxxxxx>
Acked-by: Matthew Wilcox <matthew.wilcox@xxxxxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/scsi/sym53c8xx_2/sym_hipd.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/sym53c8xx_2/sym_hipd.c b/drivers/scsi/sym53c8xx_2/sym_hipd.c
index c6425e3df5a04..f1c7714377524 100644
--- a/drivers/scsi/sym53c8xx_2/sym_hipd.c
+++ b/drivers/scsi/sym53c8xx_2/sym_hipd.c
@@ -4371,6 +4371,13 @@ static void sym_nego_rejected(struct sym_hcb *np, struct sym_tcb *tp, struct sym
 	OUTB(np, HS_PRT, HS_BUSY);
 }
 
+#define sym_printk(lvl, tp, cp, fmt, v...) do { \
+	if (cp)							\
+		scmd_printk(lvl, cp->cmd, fmt, ##v);		\
+	else							\
+		starget_printk(lvl, tp->starget, fmt, ##v);	\
+} while (0)
+
 /*
  *  chip exception handler for programmed interrupts.
  */
@@ -4416,7 +4423,7 @@ static void sym_int_sir(struct sym_hcb *np)
 	 *  been selected with ATN.  We do not want to handle that.
 	 */
 	case SIR_SEL_ATN_NO_MSG_OUT:
-		scmd_printk(KERN_WARNING, cp->cmd,
+		sym_printk(KERN_WARNING, tp, cp,
 				"No MSG OUT phase after selection with ATN\n");
 		goto out_stuck;
 	/*
@@ -4424,7 +4431,7 @@ static void sym_int_sir(struct sym_hcb *np)
 	 *  having reselected the initiator.
 	 */
 	case SIR_RESEL_NO_MSG_IN:
-		scmd_printk(KERN_WARNING, cp->cmd,
+		sym_printk(KERN_WARNING, tp, cp,
 				"No MSG IN phase after reselection\n");
 		goto out_stuck;
 	/*
@@ -4432,7 +4439,7 @@ static void sym_int_sir(struct sym_hcb *np)
 	 *  an IDENTIFY.
 	 */
 	case SIR_RESEL_NO_IDENTIFY:
-		scmd_printk(KERN_WARNING, cp->cmd,
+		sym_printk(KERN_WARNING, tp, cp,
 				"No IDENTIFY after reselection\n");
 		goto out_stuck;
 	/*
@@ -4461,7 +4468,7 @@ static void sym_int_sir(struct sym_hcb *np)
 	case SIR_RESEL_ABORTED:
 		np->lastmsg = np->msgout[0];
 		np->msgout[0] = M_NOOP;
-		scmd_printk(KERN_WARNING, cp->cmd,
+		sym_printk(KERN_WARNING, tp, cp,
 			"message %x sent on bad reselection\n", np->lastmsg);
 		goto out;
 	/*
-- 
2.20.1