@Trevor Generally when you encounter such issues, as a sysadmin we need to check what is happening in the system, we can try to find some clues in the logs using :
dmesg to check kernel ring buffer messages for any blocked tasks warnings.
You can grep "hung" in /var/log /messages to see if the processes/threads are getting hung where.
You can also check top and look for process states as "D" - that is uninterruptible sleep for kernel level I/O blocking.
These kernel level blocking typically involve uninterruptible I/O waits on blocked resources like filesystems, storage, or network mounts.
You can use "ps -eo pid,stat | grep "^D " to check the same as well.
Possible culprits for this issue could be related to NFS, SCSI timeout, disk failures or HBA issues.
check df -h for each mounts to pinpoint the hung mount issue. Then use lsof | grep pid to catch NFS errros.
Or use cat /proc/<pid>/stat to track the stuck pid where it is stuck in kernel code.
These troubleshooting methodology ca definitely help you to find the bottleneck and most importantly the ls and pwd hung as you mentioned hints towwards a mount issue ( NFS ?).
If mount/ NFS issue is there - try remount or unmount to remove the issue otherwise take a kdump before rebooting.
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