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>

1 files changed, 8 insertions, 8 deletions

diff --git a/drivers/mfd/twl-core.c b/drivers/mfd/twl-core.c
index bfbd66021af..61e70cfaa77 100644
--- 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];