[PATCH V1] accel/amdxdna: Fix potential NULL pointer dereference in context cleanup

[Lizhi Hou]

aie_destroy_context() is invoked during error handling in
aie2_create_context(). However, aie_destroy_context() assumes that the
context's mailbox channel pointer is non-NULL. If mailbox channel
creation fails, the pointer remains NULL and calling aie_destroy_context()
can lead to a NULL pointer dereference.

In aie2_create_context(), replace aie_destroy_context() with a function
which request firmware to remove the context created previously.

Fixes: be462c97b7df ("accel/amdxdna: Add hardware context")
Signed-off-by: Lizhi Hou <lizhi.hou@xxxxxxx>
---
 drivers/accel/amdxdna/aie2_message.c | 52 +++++++++++++++-------------
 1 file changed, 28 insertions(+), 24 deletions(-)

diff --git a/drivers/accel/amdxdna/aie2_message.c b/drivers/accel/amdxdna/aie2_message.c
index 03b75757a6e6..980aef9dc51a 100644
--- a/drivers/accel/amdxdna/aie2_message.c
+++ b/drivers/accel/amdxdna/aie2_message.c
@@ -192,6 +192,19 @@ int aie2_query_firmware_version(struct amdxdna_dev_hdl *ndev,
 	return 0;
 }
 
+static int aie2_destroy_context_req(struct amdxdna_dev_hdl *ndev, u32 id)
+{
+	DECLARE_AIE2_MSG(destroy_ctx, MSG_OP_DESTROY_CONTEXT);
+	struct amdxdna_dev *xdna = ndev->xdna;
+	int ret;
+
+	req.context_id = id;
+	ret = aie2_send_mgmt_msg_wait(ndev, &msg);
+	if (ret)
+		XDNA_WARN(xdna, "Destroy context failed, ret %d", ret);
+
+	return ret;
+}
 int aie2_create_context(struct amdxdna_dev_hdl *ndev, struct amdxdna_hwctx *hwctx)
 {
 	DECLARE_AIE2_MSG(create_ctx, MSG_OP_CREATE_CONTEXT);
@@ -214,13 +227,16 @@ int aie2_create_context(struct amdxdna_dev_hdl *ndev, struct amdxdna_hwctx *hwct
 		return ret;
 
 	hwctx->fw_ctx_id = resp.context_id;
-	WARN_ONCE(hwctx->fw_ctx_id == -1, "Unexpected context id");
+	if (hwctx->fw_ctx_id == -1) {
+		WARN_ON_ONCE("Unexpected context id");
+		return -EINVAL;
+	}
 
 	if (ndev->force_preempt_enabled) {
 		ret = aie2_runtime_cfg(ndev, AIE2_RT_CFG_FORCE_PREEMPT, &hwctx->fw_ctx_id);
 		if (ret) {
 			XDNA_ERR(xdna, "failed to enable force preempt %d", ret);
-			return ret;
+			goto del_ctx_req;
 		}
 	}
 
@@ -237,51 +253,39 @@ int aie2_create_context(struct amdxdna_dev_hdl *ndev, struct amdxdna_hwctx *hwct
 
 	ret = pci_irq_vector(to_pci_dev(xdna->ddev.dev), resp.msix_id);
 	if (ret == -EINVAL) {
-		XDNA_ERR(xdna, "not able to create channel");
-		goto out_destroy_context;
+		XDNA_ERR(xdna, "Alloc IRQ failed %d", ret);
+		goto del_ctx_req;
 	}
 
 	intr_reg = i2x.mb_head_ptr_reg + 4;
 	hwctx->priv->mbox_chann = xdna_mailbox_create_channel(ndev->mbox, &x2i, &i2x,
 							      intr_reg, ret);
 	if (!hwctx->priv->mbox_chann) {
-		XDNA_ERR(xdna, "not able to create channel");
+		XDNA_ERR(xdna, "Not able to create channel");
 		ret = -EINVAL;
-		goto out_destroy_context;
+		goto del_ctx_req;
 	}
 	ndev->hwctx_num++;
 
-	XDNA_DBG(xdna, "%s mailbox channel irq: %d, msix_id: %d",
-		 hwctx->name, ret, resp.msix_id);
-	XDNA_DBG(xdna, "%s created fw ctx %d pasid %d", hwctx->name,
-		 hwctx->fw_ctx_id, hwctx->client->pasid);
+	XDNA_DBG(xdna, "Mailbox channel irq: %d, msix_id: %d", ret, resp.msix_id);
+	XDNA_DBG(xdna, "Created fw ctx %d pasid %d", hwctx->fw_ctx_id, hwctx->client->pasid);
 
 	return 0;
 
-out_destroy_context:
-	aie2_destroy_context(ndev, hwctx);
+del_ctx_req:
+	aie2_destroy_context_req(ndev, hwctx->fw_ctx_id);
 	return ret;
 }
 
 int aie2_destroy_context(struct amdxdna_dev_hdl *ndev, struct amdxdna_hwctx *hwctx)
 {
-	DECLARE_AIE2_MSG(destroy_ctx, MSG_OP_DESTROY_CONTEXT);
 	struct amdxdna_dev *xdna = ndev->xdna;
 	int ret;
 
-	if (hwctx->fw_ctx_id == -1)
-		return 0;
-
 	xdna_mailbox_stop_channel(hwctx->priv->mbox_chann);
-
-	req.context_id = hwctx->fw_ctx_id;
-	ret = aie2_send_mgmt_msg_wait(ndev, &msg);
-	if (ret)
-		XDNA_WARN(xdna, "%s destroy context failed, ret %d", hwctx->name, ret);
-
+	ret = aie2_destroy_context_req(ndev, hwctx->fw_ctx_id);
 	xdna_mailbox_destroy_channel(hwctx->priv->mbox_chann);
-	XDNA_DBG(xdna, "%s destroyed fw ctx %d", hwctx->name,
-		 hwctx->fw_ctx_id);
+	XDNA_DBG(xdna, "Destroyed fw ctx %d", hwctx->fw_ctx_id);
 	hwctx->priv->mbox_chann = NULL;
 	hwctx->fw_ctx_id = -1;
 	ndev->hwctx_num--;
-- 
2.34.1