Thanks Jeff. Your patch seems to fix the problem partly, but I still get
the "device busy" error because the tun device still remains attached to
one process after eth0 is disabled in the uml.
These are the uml related processes on the host after uml is started:
[EMAIL PROTECTED]:~> pstree -p 26848
linux(26848)???linux(26855)
??linux(26856)
??linux(26857)
??linux(26858)
Each of these processes except 26855 is attached to the tun device:
[EMAIL PROTECTED]:~> lsof /dev/net/tun
COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME
linux 26848 hillenr 31u CHR 10,200 4874 /dev/net/tun
linux 26856 hillenr 31u CHR 10,200 4874 /dev/net/tun
linux 26857 hillenr 31u CHR 10,200 4874 /dev/net/tun
linux 26858 hillenr 31u CHR 10,200 4874 /dev/net/tun
After starting a telnet session to the uml telnet port, 3 more processes
are created on the host: telnetd, port-helper and another "linux"
process.
[EMAIL PROTECTED]:~> pstree -p 26848
linux(26848)???in.telnetd(27160)???port-helper(27161)
??linux(26855)
??linux(26856)
??linux(26857)
??linux(26858)
??linux(27163)
Thanks to your patch the tun device is not attached to the telnetd and
port-helper processes anymore, but still to the newly created linux
process:
[EMAIL PROTECTED]:~> lsof /dev/net/tun
COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME
linux 26848 hillenr 31u CHR 10,200 4874 /dev/net/tun
linux 26856 hillenr 31u CHR 10,200 4874 /dev/net/tun
linux 26857 hillenr 31u CHR 10,200 4874 /dev/net/tun
linux 26858 hillenr 31u CHR 10,200 4874 /dev/net/tun
linux 27163 hillenr 31u CHR 10,200 4874 /dev/net/tun
And after taking down eth0 in the uml, the tun device remains stuck in
that process until the telnet session is terminated:
[EMAIL PROTECTED]:~> lsof /dev/net/tun
COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME
linux 27163 hillenr 31u CHR 10,200 4874 /dev/net/tun
Many thanks,
Robert
> -----Original Message-----
> From: Jeff Dike [mailto:[EMAIL PROTECTED]
> Sent: Sunday, January 29, 2006 3:39 AM
> To: Robert Hillen
> Cc: user-mode-linux-user@lists.sourceforge.net
> Subject: Re: [uml-user] Not possible to enable eth0 in UML:
> Device or resource busy
>
>
> On Sun, Jan 29, 2006 at 12:08:54AM +0100, Robert Hillen wrote:
> > This happens when logging in to the uml via a telnet port.
> The problem
> > is that in this case the /dev/net/tun device remains attached to 3
> > proceses on the host:
>
> Nice diagnosis - does this patch below help?
>
> Index: linux-2.6.15-mm/arch/um/os-Linux/drivers/tuntap_user.c
> ===================================================================
> ---
> linux-2.6.15-mm.orig/arch/um/os-Linux/drivers/tuntap_user.c
> 2006-01-03 17:39:46.000000000 -0500
> +++ linux-2.6.15-mm/arch/um/os-Linux/drivers/tuntap_user.c
> 2006-01-28 21:08:13.000000000 -0500
> @@ -122,6 +122,7 @@ static int tuntap_open_tramp(char *gate,
> return(-EINVAL);
> }
> *fd_out = ((int *) CMSG_DATA(cmsg))[0];
> + os_set_exec_close(*fd_out, 1);
> return(0);
> }
>
> @@ -137,7 +138,8 @@ static int tuntap_open(void *data)
> return(err);
>
> if(pri->fixed_config){
> - pri->fd = os_open_file("/dev/net/tun",
> of_rdwr(OPENFLAGS()), 0);
> + pri->fd = os_open_file("/dev/net/tun",
> +
> of_cloexec(of_rdwr(OPENFLAGS())), 0);
> if(pri->fd < 0){
> printk("Failed to open /dev/net/tun,
> err = %d\n",
> -pri->fd);
>
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