bug#28192: TRAMP: Sometimes hangs, sometimes not

[Michael Albinus]

Michael Albinus <michael.albinus@gmx.de> writes:

Hi Alexander,

>> I observe weird behavior with TRAMP.  Sometimes it hangs, and
>> sometimes performing the same action, it does not.  Let me expand with
>> the example.  First see the attached backtrace of a hang ('hang.bt')
>> and then see the attached debug of a hang ('hang.debug').  Notice how
>> I waited for almost 3 minutes until eventually pressing <C-g> to
>> generate the backtrace and as soon as I exited the backtrace buffer,
>> the last line
>>
>> 00:36:39.418776 tramp-maybe-open-connection (3) # Opening connection
>> for root@g75vw using sudo...failed
>>
>> got printed in the debug buffer.
>>
>> What looks peculiar is this bit:
>>
>> 00:32:56.556463 tramp-send-command (6) # test -d /usr/bin 2>/dev/null;
>> echo tramp_exit_status $?
>> 00:32:57.493123 tramp-send-command (6) # test -e /\*scratch\*
>> 2>/dev/null; echo tramp_exit_status $?
>> 00:32:57.567582 tramp-wait-for-regexp (6) #
>> tramp_exit_status 1
>> ///deee5cb9d3522d2a1faeef9e0327d4f1#$
>> 00:33:57.490307 tramp-send-command (6) # test -e /\*scratch\*
>> 2>/dev/null; echo tramp_exit_status $?
>> 00:33:57.491565 tramp-wait-for-regexp (6) #
>> tramp_exit_status 1
>> ///deee5cb9d3522d2a1faeef9e0327d4f1#$
>>
>> That is where did the status of '/usr/bin' test go?  And why on earth
>> would '*scratch*' be tested?  I verified and files like with
>> '*scratch*' names of course do not exist.  It looks like TRAMP hangs
>> after these tests.
>
> There are even more dubious tests. See for example
>
>> 00:21:44.114726 tramp-send-command (6) # test -e /\>copy-region-as-kill 
>> 2>/dev/null; echo tramp_exit_status $?
>
> I doubt, that you have a file "/>copy-region-as-kill".
>
>> Phew...  Any ideas where to start looking?
>
> Does the same problem happen if you start
>
> # emacs -Q --eval '(setq tramp-verbose 6)'

Several months without an answer, so I'm closing this. Feel free to
reopen if you could contribute.

>> Regards,
>> Alexander

Best regards, Michael.