[PATCH] soc: imx: imx8m-blk-ctrl: Fix NULL pointer dereference

[Ma Ke]

Check bc->bus_power_dev = dev_pm_domain_attach_by_name() return value using
IS_ERR_OR_NULL() instead of plain IS_ERR(), and fail if bc->bus_power_dev 
is either error or NULL.

In case a power domain attached by dev_pm_domain_attach_by_name() is not
described in DT, dev_pm_domain_attach_by_name() returns NULL, which is
then used, which leads to NULL pointer dereference.

Found by code review.

Cc: stable at vger.kernel.org
Fixes: 1a1da28544fd ("soc: imx: imx8m-blk-ctrl: Defer probe if 'bus' genpd is not yet ready")
Signed-off-by: Ma Ke <make24 at iscas.ac.cn>
---
 drivers/pmdomain/imx/imx8m-blk-ctrl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pmdomain/imx/imx8m-blk-ctrl.c b/drivers/pmdomain/imx/imx8m-blk-ctrl.c
index ca942d7929c2..d46fb5387148 100644
--- a/drivers/pmdomain/imx/imx8m-blk-ctrl.c
+++ b/drivers/pmdomain/imx/imx8m-blk-ctrl.c
@@ -212,7 +212,7 @@ static int imx8m_blk_ctrl_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	bc->bus_power_dev = dev_pm_domain_attach_by_name(dev, "bus");
-	if (IS_ERR(bc->bus_power_dev)) {
+	if (IS_ERR_OR_NULL(bc->bus_power_dev)) {
 		if (PTR_ERR(bc->bus_power_dev) == -ENODEV)
 			return dev_err_probe(dev, -EPROBE_DEFER,
 					     "failed to attach power domain \"bus\"\n");
-- 
2.25.1