Error with command iotop on CentOS

Question

When using sudo iotop (latest version 0.6-2.el7) in a terminal in my newly installed CentOS 7.5, I get the following error message:

Traceback (most recent call last):
  File "/sbin/iotop", line 17, in <module>
    main()
  File "/usr/lib/python2.7/site-packages/iotop/ui.py", line 620, in main
    main_loop()
  File "/usr/lib/python2.7/site-packages/iotop/ui.py", line 610, in <lambda>
    main_loop = lambda: run_iotop(options)
  File "/usr/lib/python2.7/site-packages/iotop/ui.py", line 508, in run_iotop
    return curses.wrapper(run_iotop_window, options)
  File "/usr/lib64/python2.7/curses/wrapper.py", line 43, in wrapper
    return func(stdscr, *args, **kwds)
  File "/usr/lib/python2.7/site-packages/iotop/ui.py", line 501, in run_iotop_window
    ui.run()
  File "/usr/lib/python2.7/site-packages/iotop/ui.py", line 155, in run
    self.process_list.duration)
  File "/usr/lib/python2.7/site-packages/iotop/ui.py", line 434, in refresh_display
    lines = self.get_data()
  File "/usr/lib/python2.7/site-packages/iotop/ui.py", line 415, in get_data
    return list(map(format, processes))
  File "/usr/lib/python2.7/site-packages/iotop/ui.py", line 388, in format
    cmdline = p.get_cmdline()
  File "/usr/lib/python2.7/site-packages/iotop/data.py", line 292, in get_cmdline
    proc_status = parse_proc_pid_status(self.pid)
  File "/usr/lib/python2.7/site-packages/iotop/data.py", line 196, in parse_proc_pid_status
    key, value = line.split(':\t', 1)
ValueError: need more than 1 value to unpack

Any idea how to fix this problem?

Answer 1

Apparently, recent kernel versions introduced a blank line in /proc/(pid)/status that iotop does not expect:

CapBnd: 0000001fffffffff
CapAmb: 0000000000000000
Seccomp:    0

SpeculationStoreBypass: vulnerable

As a zeroth approximation of a fix, edit (as root) /usr/lib/python2.7/site-packages/iotop/data.py ca l.195:

def parse_proc_pid_status(pid):
    result_dict = {}
    try:
        for line in open('/proc/%d/status' % pid):
            if not line.strip(): continue
            key, value = line.split(':\t', 1)
            result_dict[key] = value.strip()
    except IOError:
        pass  # No such process

    return result_dict

where the if not line.strip(): continue is new. Beware that python does not have explicit braces, so the indentation of this line should match that of the line below it.

(Also see https://bugs.launchpad.net/pkg-website/+bug/1773383 for other fixes for this bug.)

Answer 2

Just to complement the accepted answer (couldn't add as comment because they don't allow multiple white spaces)

1. Search for the filepath of the Python script

sudo find ./usr/lib | grep iotop/data.py

2. Replace with sed

sed -i '1n;/key, value = line/i\            if not line.strip(): continue' <script_path>

Be careful and check everything is ok the first time you run it.

For my systems, it is:

sudo sed -i '1n;/key, value = line/i\            if not line.strip(): continue' /usr/lib/python2.7/dist-packages/iotop/data.py