Re: [PATCH/RFC] gdbserver: Add command line option to not use SO_REUSEADDR

[Tom Tromey <tom at tromey dot com>]

>>>>> "Alan" == Alan Hayward <Alan.Hayward@arm.com> writes:

Alan> (Not sure if there is any additional documentation that will need
Alan>  updating alongside this patch, or any other additions that need
Alan>  to go alongside new command line flags).

There is some documentation on invoking gdbserver in the manual, so that
should be updated.

Alan> Forcing on gdb and gdbserver debug shows that for the failure cases
Alan> gdbserver is launched, connects to gdb and sucessfully sends and
Alan> receives packets.  Meanwhile on the gdb side, no packets are sent or
Alan> received and the connection simply times out.  This indicates that
Alan> the gdb from another running test has connected to this gdbserver.

Could you walk me through how this happens?  It seems strange to me that
there could be any kind of race.  What I don't understand is that if two
tests can run in parallel, both start gdbserver, and then one gdb can
connect to the wrong server -- then it seems to me that the bug must be
in the test suite itself?

Alan> When running with -j55 on HEAD

Jealous.

Alan> 2019-02-12  Alan Hayward  <alan.hayward@arm.com>
Alan> 	* remote-utils.c (remote_prepare): Check reuse flag.
Alan> 	* server.c (gdbserver_usage): Add reuse help messages.
Alan> 	(captured_main): Check for reuse flags
Alan> 	* server.h (struct client_state): Add reuse flag.

FWIW the contents of the patch all seem fine to me.  But, I'd like to
understand the problem better before approving it (and also there's the
documentation).

thanks,
Tom