[PATCH 4.4 074/268] scsi: sym53c8xx_2: iterator underflow in sym_getsync()

From: Greg Kroah-Hartman
Date: Mon May 28 2018 - 11:43:46 EST


4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Dan Carpenter <dan.carpenter@xxxxxxxxxx>

[ Upstream commit e6f791d95313c85f3dd4a26141e28e50ae9aa0ae ]

We wanted to exit the loop with "div" set to zero, but instead, if we
don't hit the break then "div" is -1 when we finish the loop. It leads
to an array underflow a few lines later.

Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Reviewed-by: Johannes Thumshirn <jthumshirn@xxxxxxx>
Acked-by: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/scsi/sym53c8xx_2/sym_hipd.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/scsi/sym53c8xx_2/sym_hipd.c
+++ b/drivers/scsi/sym53c8xx_2/sym_hipd.c
@@ -536,7 +536,7 @@ sym_getsync(struct sym_hcb *np, u_char d
* Look for the greatest clock divisor that allows an
* input speed faster than the period.
*/
- while (div-- > 0)
+ while (--div > 0)
if (kpc >= (div_10M[div] << 2)) break;

/*