Question about WCHAN values

UNIX for Beginners Q & A
1

I have a CentOS 8 (3.10) running on VirtualBox 6.0... And I have 2 questions about WCHAN

The 'ps' man page describes WCHAN as:

I haven't see the "*" yet, but I'll see a "?" in the output of the "ps" command with regularity. Usually associated with the rcu_sched kernel process, but the "?" does appear for other processes. I haven't found a definition for the "?"... What does it mean?

My 2nd question is about a discrepancy I'm seeing between the output of the 'ps' command and the 'System Monitor' GUI utility. Under the 'ps' command, I'll see several processes in a run state and will have a "-" under WCHAN. Yet under the "System Monitor", those same processes will be in a run state with a WCHAN code of "poll_schedule_timeout". From what I've read this indicates a process is waiting for I/O... Shouldn't these processes be in a sleep state?

2

Hi
How to look at a sample line with '?' and headers
Thanks

3

Thanks for the reply... Here's the output you asked for

4

I'm at a loss. It remains to assume either the remote NFS or LXC container