Re: Can only connect to RMS gateway once

[David Ranch <linux-hams@trinnet.net>]

Hey Basil,

Good to hear from you.. hope all is well.

Yes.. it's been reported and Thomas verified it but I haven't heard of 
any fixes yet ( I did send out a prod last month but no response)

--David
KI6ZHD



-------- Forwarded Message --------
Subject: 	Re: AX.25 / ax25d socket close issue on Ubuntu 14.04 but not 
on 12.04
Date: 	Tue, 29 Mar 2016 09:00:37 +0200
From: 	Thomas Osterried <thomas@de>
To: 	David Ranch <dranch@net>
CC: 	Ralf Bächle DL5RB <ralf@org>, Bernard, f6bvp <f6bvp@fr>



> Am 28.03.2016 um 22:21 schrieb David Ranch <dranch@net>:
>
> Hey Ralf, Thomas, Bernard,
>
> I've been helping a user here who is running the LinuxRMS gateway on his Ubuntu 14.04 machine and when the remote station terminates the session, it leaves an AX.25 session on his computer *forever*.. never times out:
>
> Active AX.25 sockets
> Dest       Source     Device  State        Vr/Vs    Send-Q  Recv-Q
> WA7FPV-0   WA7FPV-10  ax0     LISTENING    001/003  0       0
>
> He built up an Ubuntu 12.04 machine with the same LinuxRMS/ax25d service and this does NOT happen.  He then sent me the below strace.  Any thoughts on where this issue is coming from?

Hello David,

just for a quick answer (I'm on journey): it's coming from a kernel bug in the ax25 part.
You already have Cc'ed Ralf <dl5rb>.
If I remember correctly, he spoke some weeks ago also about this issue.
I also know of those problems, which are very rare.

My question is: does it happen on SMP (multiprocessor-machine)?

vy 73,
	- Thomas  dl9sau

>
> --David
>
>
>
> -------- Forwarded Message --------
> Subject:	Re: AX.25 Help...
> Date:	Mon, 28 Mar 2016 12:52:25 -0700
> From:	Josh Gibbs <gibbsjj@com>
> To:	David Ranch <dranch@net>
>
> Confirmed that starting Direwolf on the Ubuntu 14 box with your script made no difference. Socket still hangs up. I connected to the rmsgw process with strace, and then sent the bye command:
>
> select(5, [0 4], NULL, NULL, NULL)      = 1 (in [0])
> read(0, "b\r", 8192)                    = 2
> write(4, "b\r", 2)                      = 2
> read(0, 0x8058180, 8192)                = -1 EAGAIN (Resource temporarily unavailable)
> select(5, [0 4], NULL, NULL, NULL)      = 1 (in [4])
> recv(4, "D", 1, MSG_PEEK|MSG_DONTWAIT)  = 1
> recv(4, "Disconnecting...\r", 8192, 0)  = 17
> write(1, "Disconnecting...\r", 17)      = 17
> recv(4, 0x8058180, 8192, 0)             = -1 EAGAIN (Resource temporarily unavailable)
> select(5, [0 4], NULL, NULL, NULL)      = 1 (in [4])
> recv(4, "", 1, MSG_PEEK|MSG_DONTWAIT)   = 0
> time(NULL)                              = 1459193715
> send(3, "<134>Mar 28 12:35:15 rmsgw[1417]"..., 85, MSG_NOSIGNAL) = 85
> write(1, "; INFO: Connection closed by CMS"..., 51) = 51
> rt_sigprocmask(SIG_BLOCK, [CHLD], [], 8) = 0
> rt_sigaction(SIGCHLD, NULL, {SIG_IGN, [], 0}, 8) = 0
> nanosleep({1, 0}, 0xbfad3bac)           = 0
> rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
> close(4)                                = 0
> time(NULL)                              = 1459193716
> write(1, "; Sent: 81 Bytes / Received: 2 B"..., 61) = 61
> write(1, "; W7AUX de WA7FPV-10 SK\n", 24) = 24
> time(NULL)                              = 1459193716
> time(NULL)                              = 1459193716
> send(3, "<133>Mar 28 12:35:16 rmsgw[1417]"..., 84, MSG_NOSIGNAL) = 84
> close(4)                                = -1 EBADF (Bad file descriptor)
> exit_group(0)                           = ?
> +++ exited with 0 +++
>
> I'm thinking that close(4) near the end is supposed to close the socket, but is resulting in -1 EBADF (Bad file descriptor).
>
> I'm going to have a look in the code when I have more time to poke at this, but for now I at least have a working RMS Gateway on the Ubuntu 12 box! Appreciate all your help with this. I will let you know when I get to the root of it all, if you are interested!
>
> -Josh
>
>

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