4.19-stable review patch. If anyone has any objections, please let me know.
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From: Herve Codina herve.codina@bootlin.com
commit 3dc0ec46f6e7511fc4fdf6b6cda439382bc957f1 upstream.
i2c-mux-gpmux uses the pair of_find_i2c_adapter_by_node() / i2c_put_adapter(). These pair alone is not correct to properly lock the I2C parent adapter.
Indeed, i2c_put_adapter() decrements the module refcount while of_find_i2c_adapter_by_node() does not increment it. This leads to an underflow of the parent module refcount.
Use the dedicated function, of_get_i2c_adapter_by_node(), to handle correctly the module refcount.
Fixes: ac8498f0ce53 ("i2c: i2c-mux-gpmux: new driver") Signed-off-by: Herve Codina herve.codina@bootlin.com Cc: stable@vger.kernel.org Acked-by: Peter Rosin peda@axentia.se Reviewed-by: Jonathan Cameron Jonathan.Cameron@huawei.com Signed-off-by: Wolfram Sang wsa@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/i2c/muxes/i2c-mux-gpmux.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/i2c/muxes/i2c-mux-gpmux.c +++ b/drivers/i2c/muxes/i2c-mux-gpmux.c @@ -55,7 +55,7 @@ static struct i2c_adapter *mux_parent_ad dev_err(dev, "Cannot parse i2c-parent\n"); return ERR_PTR(-ENODEV); } - parent = of_find_i2c_adapter_by_node(parent_np); + parent = of_get_i2c_adapter_by_node(parent_np); of_node_put(parent_np); if (!parent) return ERR_PTR(-EPROBE_DEFER);