[33/75] mfd: Fix twl-core oops while calling twl_i2c_* for unbound driver

[Greg KH]

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

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

From: Ilya Yanok <yanok@xxxxxxxxxxx>

commit 8653be1afd60d6e8c36139b487e375b70357d9ef upstream.

Check inuse variable before trying to access twl_map to prevent
dereferencing of uninitialized variable.

Signed-off-by: Ilya Yanok <yanok@xxxxxxxxxxx>
Signed-off-by: Samuel Ortiz <sameo@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 drivers/mfd/twl-core.c |   16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

--- a/drivers/mfd/twl-core.c
+++ b/drivers/mfd/twl-core.c
@@ -362,13 +362,13 @@ int twl_i2c_write(u8 mod_no, u8 *value,
 		pr_err("%s: invalid module number %d\n", DRIVER_NAME, mod_no);
 		return -EPERM;
 	}
-	sid = twl_map[mod_no].sid;
-	twl = &twl_modules[sid];
-
 	if (unlikely(!inuse)) {
-		pr_err("%s: client %d is not initialized\n", DRIVER_NAME, sid);
+		pr_err("%s: not initialized\n", DRIVER_NAME);
 		return -EPERM;
 	}
+	sid = twl_map[mod_no].sid;
+	twl = &twl_modules[sid];
+
 	mutex_lock(&twl->xfer_lock);
 	/*
 	 * [MSG1]: fill the register address data
@@ -419,13 +419,13 @@ int twl_i2c_read(u8 mod_no, u8 *value, u
 		pr_err("%s: invalid module number %d\n", DRIVER_NAME, mod_no);
 		return -EPERM;
 	}
-	sid = twl_map[mod_no].sid;
-	twl = &twl_modules[sid];
-
 	if (unlikely(!inuse)) {
-		pr_err("%s: client %d is not initialized\n", DRIVER_NAME, sid);
+		pr_err("%s: not initialized\n", DRIVER_NAME);
 		return -EPERM;
 	}
+	sid = twl_map[mod_no].sid;
+	twl = &twl_modules[sid];
+
 	mutex_lock(&twl->xfer_lock);
 	/* [MSG1] fill the register address data */
 	msg = &twl->xfer_msg[0];


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