Re: Testing with remote gdbserver

[Simon Marchi <simon dot marchi at polymtl dot ca>]

On 2018-02-08 09:29, Dmitry Antipov wrote:
> Hello,
>
> are there any known-to-work board configuration files to test
> gdbserver remotely?
> After reading https://sourceware.org/gdb/wiki/TestingGDB, I supposed 
> that this
> has to be relatively simple, at least between two GNU/Linux x86
> machines with public
> key-based ssh access between them. But, since I just have a) noise
> about missing 'runtest'
> (which is /usr/bin/runtest in my $PATH), b) a lot of FAILED messages
> (probably due to
> communication timeouts) and c) time-to-time zombie ssh processes, I
> assume that my setup
> is grossly misconfigured at some non-obvious but very important point.
> I've started
> from example remote board file taken from "Testing gdbserver in a
> remote cross-target
> configuration" of the above and tried some tweaks, but still have no
> PASSes (except
> for local libiberty tests). Is it possible to run the tests in a "much
> more verbose"
> mode to check what's going on?
>
> Thanks in advance,
> Dmitry

The remote-stdio-gdbserver.exp board should work, but be aware of this 
issue that was reported recently:

  https://sourceware.org/ml/gdb/2018-01/msg00023.html

I just tried it and stumbled on another bug, if you are using 
gdb/gdbserver 8.1.  You might get something like this in gdb.log:

(gdb) target remote | /usr/bin/ssh simark@s.thetu.bz /usr/bin/gdbserver 
--once stdio jump
Remote debugging using | /usr/bin/ssh simark@s.thetu.bz 
/usr/bin/gdbserver --once stdio jump
stdin/stdout redirected
zsh:1: command not found: jump
During startup program exited with code 127.

This is likely caused by the fact that gdbserver now starts (by default) 
the inferior process through a shell.  If you run "gdbserver ... jump", 
it will try to run the "jump" command through the shell, which is not 
found because it's not in the path.  I worked around it by doing this 
simple change:

diff --git a/gdb/testsuite/boards/remote-stdio-gdbserver.exp 
b/gdb/testsuite/boards/remote-stdio-gdbserver.exp
index aff7902..3e01d1b 100644
--- a/gdb/testsuite/boards/remote-stdio-gdbserver.exp
+++ b/gdb/testsuite/boards/remote-stdio-gdbserver.exp
@@ -70,7 +70,7 @@ proc get_remote_login { } {
 proc get_target_remote_pipe_cmd { } {
     set target_exec [gdbserver_download_current_prog]
     set rsh_cmd "[board_info [target_info name] rsh_prog] 
[get_remote_login]"
-    return "$rsh_cmd /usr/bin/gdbserver --once stdio $target_exec"
+    return "$rsh_cmd /usr/bin/gdbserver --once stdio ./$target_exec"
 }

 proc ${board}_file { dest op args } {


With this I'm able to test using a remote gdbserver between two x86 
machines (though note that it uses the gdbserver on the target machine, 
the testsuite doesn't upload it itself).

Simon