mfd: Fix twl-core oops while calling twl_i2c_* for unbound driver

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

Signed-off-by: Ilya Yanok <yanok@emcraft.com>
Cc: stable@kernel.org
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

diff --git a/drivers/mfd/twl-core.c b/drivers/mfd/twl-core.c
index bfbd660..61e70cf 100644 (file)
--- a/drivers/mfd/twl-core.c
+++ b/drivers/mfd/twl-core.c
@@ -363,13 +363,13 @@ int twl_i2c_write(u8 mod_no, u8 *value, u8 reg, unsigned num_bytes)
                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
@@ -420,13 +420,13 @@ int twl_i2c_read(u8 mod_no, u8 *value, u8 reg, unsigned num_bytes)
                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];