Unexpected error log appears with debug image

[liuw1]

INFO - MigTD Version - 0.5.1
ERROR - query: Failed to allocate command shared memoryERROR - query: Failed to allocate response shared memoryERROR - query: Failed to create VmcallServiceCommandERROR - query: Failed to create VmcallServiceResponseERROR - query: Failed to copy response to private shadow
ERROR - query: Failed to read VmcallServiceResponse from response
ERROR - query: Failed to read ServiceQueryResponse from response
INFO - Migration is supported by VMM
ERROR - receive_hello_packet: Failed to read PreSessionMessage header
INFO - Pre-Session-Message Version: 0x0100
ERROR - receive_pre_session_data_packet: Failed to read PreSessionMessage header
ERROR - receive_start_session_packet: Failed to read PreSessionMessage header

[gaojiaqi7]

Hi @agokarn , please take a look at this issue.

• Please use ok_or_else instead of ok_or when handling possible None values. ok_or always runs its argument—even when Some—so it would emit logs unnecessarily.
• Also ensure every log call ends with a newline '\n'.

[gaojiaqi7]

Regression caused by a2228fc

[jyao1]

@agokarn , since this is a regression, would you please take a look and fix?

[agokarn]

@jyao1 this is not really a regression. Earlier we didnt log "query: Failed to allocate command shared memory", now we do. In some cases there is no \n added.

@haitaohuang has a fix for this and will be submitting it shortly

[jyao1]

@agokarn and @haitaohuang
What is expectation for "log::error!" now?
I notice some of them having the "\n", but some not.

[gaojiaqi7]

Hi @agokarn , please be aware that these are unexpected error logs generated from correct execution results.

For example:

https://github.com/intel/MigTD/blob/main/src/migtd/src/migration/session.rs#L115-L118

    let mut cmd_mem = SharedMemory::new(1).ok_or({
        log::error!("query: Failed to allocate command shared memory");
        MigrationResult::OutOfResource
    })?;

The log is dumped even if SharedMemory::new(1) returns Some(val).

If you want to dump error log in case of None you need to use ok_or_else instead of ok_or.

This is a regression because we do not dump error in success case.

[jyao1]

@jyao1 this is not really a regression. Earlier we didnt log "query: Failed to allocate command shared memory", now we do.

@agokarn , I do no agree because you dump error log in success case, not error case.
This is a regression. Please fix it.

[agokarn]

@jyao1 this is not really a regression. Earlier we didnt log "query: Failed to allocate command shared memory", now we do.

@agokarn , I do no agree because you dump error log in success case, not error case. This is a regression. Please fix it.

Agree! Sorry about the regression. @haitaohuang has a PR almost ready. How urgent is this?

[agokarn]

@jyao1 this is not really a regression. Earlier we didnt log "query: Failed to allocate command shared memory", now we do.

@agokarn , I do no agree because you dump error log in success case, not error case. This is a regression. Please fix it.

Agree! Sorry about the regression. @haitaohuang has a PR almost ready. How urgent is this?

@jyao1 , @haitaohuang already has created a PR for this - #645

[jyao1]

Great. I approved #645. Once CI passes, I will merge.