If driver read tmp (or val) value sufficient for (tmp & 0x08) && (!(tmp & 0x80)) && ((tmp & 0x7) == ((tmp >> 4) & 0x7)) from device then Null pointer dereference occurs. (It is possible if tmp = 0b0xyz1xyz, where same literals mean same numbers) The patch adds checking if data->lm75[0] is NULL. Found by Linux Driver Verification project (linuxtesting.org). Signed-off-by: Nadezda Lutovinova <lutovinova@xxxxxxxxx> --- drivers/hwmon/w83791d.c | 2 +- drivers/hwmon/w83792d.c | 2 +- drivers/hwmon/w83793.c | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/hwmon/w83791d.c b/drivers/hwmon/w83791d.c index 37b25a1474c4..8b30bbfafaa7 100644 --- a/drivers/hwmon/w83791d.c +++ b/drivers/hwmon/w83791d.c @@ -1284,7 +1284,7 @@ static int w83791d_detect_subclients(struct i2c_client *client) data->lm75[0] = devm_i2c_new_dummy_device(&client->dev, adapter, 0x48 + (val & 0x7)); if (!(val & 0x80)) { - if (!IS_ERR(data->lm75[0]) && + if (!IS_ERR_OR_NULL(data->lm75[0]) && ((val & 0x7) == ((val >> 4) & 0x7))) { dev_err(&client->dev, "duplicate addresses 0x%x, " diff --git a/drivers/hwmon/w83792d.c b/drivers/hwmon/w83792d.c index abd5c3a722b9..85ae12d950e1 100644 --- a/drivers/hwmon/w83792d.c +++ b/drivers/hwmon/w83792d.c @@ -950,7 +950,7 @@ w83792d_detect_subclients(struct i2c_client *new_client) data->lm75[0] = devm_i2c_new_dummy_device(&new_client->dev, adapter, 0x48 + (val & 0x7)); if (!(val & 0x80)) { - if (!IS_ERR(data->lm75[0]) && + if (!IS_ERR_OR_NULL(data->lm75[0]) && ((val & 0x7) == ((val >> 4) & 0x7))) { dev_err(&new_client->dev, "duplicate addresses 0x%x, use force_subclient\n", diff --git a/drivers/hwmon/w83793.c b/drivers/hwmon/w83793.c index e7d0484eabe4..9d8c44e2fa6e 100644 --- a/drivers/hwmon/w83793.c +++ b/drivers/hwmon/w83793.c @@ -1590,7 +1590,7 @@ w83793_detect_subclients(struct i2c_client *client) data->lm75[0] = devm_i2c_new_dummy_device(&client->dev, adapter, 0x48 + (tmp & 0x7)); if (!(tmp & 0x80)) { - if (!IS_ERR(data->lm75[0]) + if (!IS_ERR_OR_NULL(data->lm75[0]) && ((tmp & 0x7) == ((tmp >> 4) & 0x7))) { dev_err(&client->dev, "duplicate addresses 0x%x, " -- 2.17.1