Code used from github: https://github.com/opencontainers/runc/blob/master/libcontainer/rootfs_linux.go#L59
This is the if block to debug for our interest....
if err := mountToRootfs(m, config.Rootfs, config.MountLabel, hasCgroupns); err != nil {
return newSystemErrorWithCausef(err, "mounting %q to rootfs at %q", m.Source, m.Destination)
}
Here in the if condition, there is an error generated thru newSystemErrorWithCausef function and which internally uses generic_error.go, fmt.Sprintf to format the error string. In our integration, only once it hit this if block. And in the process of getting more details, I wanted to troubleshoot and understand why this happened.
As of now tried using fmt.Printf(........) in line 55 and also just before if block of line 59. And also tried putting above statement in very first line of prepareRootfs function. And then tried newSystemErrorWithCause(err, "some other message") in the first line of prepareRootfs function. Overall I dont see any information generated with my messages.
Please provide any information to understand more of this issue. Please note I am not looking for why this error might have been caused. I am looking for how to get more information from that function of prepareRootfs.