Exception Due to Invalid Read/Write Buffer Address

Symptom

The kernel-space log on the device reports an error indicating that the VPC has an exception. (The error log in different version may be different.)

• Log 1

  vpc get err int: vpc_cvdr_axi_rd_resp_err

• Log 2

  vpc get err int: vpc_cvdr_axi_wr_resp_err

Possible Cause

• cvdr_axi_rd_resp_err indicates out-of-bounds read. This is possibly because the allocated input buffer is too small or the buffer address is invalid. As a result, the Ascend AI Processor accesses an invalid address when performing the read operation.
• cvdr_axi_wr_resp_err indicates out-of-bounds write. This is possibly because the allocated output buffer is too small or the buffer address is invalid. As a result, the Ascend AI Processor accesses an invalid address when performing the write operation.

Solution

1. Add log printing to the API for allocating DVPP buffer and the API for an abnormal VPC task. Check whether the allocated input/output buffer size is the same as the actually used input/output buffer size.

2. Add log printing to the API for releasing DVPP buffer to check whether the buffer is released before the VPC task is complete.