linux-kernel - Re: [PATCH V2] accel/amdxdna: Fix potential NULL pointer dereference in context cleanup

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Message-ID: <10c70508-45e2-8b2e-6277-e874f4c5bff4@amd.com>
Date: Mon, 15 Dec 2025 10:01:13 -0800
From: Lizhi Hou <lizhi.hou@....com>
To: Mario Limonciello <mario.limonciello@....com>, <ogabbay@...nel.org>,
	<quic_jhugo@...cinc.com>, <dri-devel@...ts.freedesktop.org>,
	<maciej.falkowski@...ux.intel.com>
CC: <linux-kernel@...r.kernel.org>, <max.zhen@....com>, <sonal.santan@....com>
Subject: Re: [PATCH V2] accel/amdxdna: Fix potential NULL pointer dereference
 in context cleanup

Applied to drm-misc-next

On 12/12/25 10:56, Mario Limonciello wrote:
> On 12/12/25 12:32 PM, Lizhi Hou wrote:
>> 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@....com>
> Reviewed-by: Mario Limonciello (AMD) <superm1@...nel.org>> ---
>>   drivers/accel/amdxdna/aie2_message.c | 50 +++++++++++++++-------------
>>   1 file changed, 26 insertions(+), 24 deletions(-)
>>
>> diff --git a/drivers/accel/amdxdna/aie2_message.c 
>> b/drivers/accel/amdxdna/aie2_message.c
>> index 03b75757a6e6..9ec973028221 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 +227,14 @@ 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 (WARN_ON_ONCE(hwctx->fw_ctx_id == -1))
>> +        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 +251,39 @@ 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--;
>