mhi_alloc_controller() allocates a memory space for mhi_ctrl. When some
errors occur, mhi_ctrl should be freed by mhi_free_controller() and set
ab_pci->mhi_ctrl = NULL because ab_pci->mhi_ctrl has a dangling pointer
to the freed memory. But when ath11k_mhi_read_addr_from_dt() fails, the
function returns without calling mhi_free_controller(), which will lead
to a memory leak.

We can fix it by calling mhi_free_controller() when
ath11k_mhi_read_addr_from_dt() fails and set ab_pci->mhi_ctrl = NULL in
all of the places where we call mhi_free_controller().

Signed-off-by: Jianglei Nie <redacted>
---
  drivers/net/wireless/ath/ath11k/mhi.c | 17 ++++++++++-------
  1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/drivers/net/wireless/ath/ath11k/mhi.c b/drivers/net/wireless/ath/ath11k/mhi.c
index fc3524e83e52..fc1bbf91c58e 100644
--- a/drivers/net/wireless/ath/ath11k/mhi.c
+++ b/drivers/net/wireless/ath/ath11k/mhi.c

@@ -367,8 +367,7 @@ int ath11k_mhi_register(struct ath11k_pci *ab_pci)
  	ret = ath11k_mhi_get_msi(ab_pci);
  	if (ret) {
  		ath11k_err(ab, "failed to get msi for mhi\n");
-		mhi_free_controller(mhi_ctrl);
-		return ret;
+		goto free_controller;
  	}
  
  	if (!test_bit(ATH11K_PCI_FLAG_MULTI_MSI_VECTORS, &ab_pci->flags))

@@ -377,7 +376,7 @@ int ath11k_mhi_register(struct ath11k_pci *ab_pci)
  	if (test_bit(ATH11K_FLAG_FIXED_MEM_RGN, &ab->dev_flags)) {
  		ret = ath11k_mhi_read_addr_from_dt(mhi_ctrl);
  		if (ret < 0)
-			return ret;
+			goto free_controller;
  	} else {
  		mhi_ctrl->iova_start = 0;
  		mhi_ctrl->iova_stop = 0xFFFFFFFF;

@@ -405,18 +404,22 @@ int ath11k_mhi_register(struct ath11k_pci *ab_pci)
  	default:
  		ath11k_err(ab, "failed assign mhi_config for unknown hw rev %d\n",
  			   ab->hw_rev);
-		mhi_free_controller(mhi_ctrl);
-		return -EINVAL;
+		ret = -EINVAL;
+		goto free_controller;
  	}
  
  	ret = mhi_register_controller(mhi_ctrl, ath11k_mhi_config);
  	if (ret) {
  		ath11k_err(ab, "failed to register to mhi bus, err = %d\n", ret);
-		mhi_free_controller(mhi_ctrl);
-		return ret;
+		goto free_controller;
  	}
  
  	return 0;
+
+free_controller:
+	mhi_free_controller(mhi_ctrl);
+	ab_pci->mhi_ctrl = NULL;
+	return ret;
  }
  
  void ath11k_mhi_unregister(struct ath11k_pci *ab_pci)