[PATCH 4.9 64/86] scsi: ufs: ufshcd: fix potential NULL pointer dereference in ufshcd_config_vreg

From: Greg Kroah-Hartman
Date: Fri Feb 02 2018 - 12:10:44 EST


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

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

From: "Gustavo A. R. Silva" <garsilva@xxxxxxxxxxxxxx>


[ Upstream commit 727535903bea924c4f73abb202c4b3e85fff0ca4 ]

_vreg_ is being dereferenced before it is null checked, hence there is a
potential null pointer dereference.

Fix this by moving the pointer dereference after _vreg_ has been null
checked.

This issue was detected with the help of Coccinelle.

Fixes: aa4976130934 ("ufs: Add regulator enable support")
Signed-off-by: Gustavo A. R. Silva <garsilva@xxxxxxxxxxxxxx>
Reviewed-by: Subhash Jadavani <subhashj@xxxxxxxxxxxxxx>
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/ufs/ufshcd.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -5327,12 +5327,15 @@ static int ufshcd_config_vreg(struct dev
struct ufs_vreg *vreg, bool on)
{
int ret = 0;
- struct regulator *reg = vreg->reg;
- const char *name = vreg->name;
+ struct regulator *reg;
+ const char *name;
int min_uV, uA_load;

BUG_ON(!vreg);

+ reg = vreg->reg;
+ name = vreg->name;
+
if (regulator_count_voltages(reg) > 0) {
min_uV = on ? vreg->min_uV : 0;
ret = regulator_set_voltage(reg, min_uV, vreg->max_uV);