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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        "Gustavo A. R. Silva" <garsilva@embeddedor.com>,
        Subhash Jadavani <subhashj@codeaurora.org>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        Sasha Levin <alexander.levin@microsoft.com>
Subject: [PATCH 4.4 51/67] scsi: ufs: ufshcd: fix potential NULL pointer dereference in ufshcd_config_vreg
Date:   Fri,  2 Feb 2018 17:58:20 +0100
Message-Id: <20180202140820.995188551@linuxfoundation.org>
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4.4-stable review patch.  If anyone has any objections, please let me know.

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

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


[ 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@embeddedor.com>
Reviewed-by: Subhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 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
@@ -4392,12 +4392,15 @@ 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);