[lldb-dev] Remote debugging ARM target from x86 host

Wed Aug 23 11:31:18 PDT 2017

What should be happening is Handle_qLaunchGDBServer calls LaunchGDBServer with a port of UINT16_MAX, which tells it to use a port in its port list. It shouldn't have a port list, so should return 0. LaunchGDBServer calls StartDebugServerProcess with a port of 0 in the url. StartDebugServerProcess launches the gdbserver with a named pipe, and reads the actual port from the pipe.

I suggest turning on more logging - specifically, "gdb-remote process". That's the channel used in StartDebugServerProcess.

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> -----Original Message-----
> From: lldb-dev [mailto:lldb-dev-bounces at lists.llvm.org] On Behalf Of Greg
> Clayton via lldb-dev
> Sent: Wednesday, August 23, 2017 12:45 PM
> To: Hans Wennborg <hans at chromium.org>
> Cc: Ramana <ramana.venkat83 at gmail.com>; LLDB Dev <lldb-
> dev at lists.llvm.org>
> Subject: Re: [lldb-dev] Remote debugging ARM target from x86 host
> 
> Port zero should never be returned as a valid port. We do bind to port zero just
> so we don't try and pick a port at random just to find it is being used. When we
> bind to port 9, we must find the actual port we bound to and return that. Seems
> something has gone wrong with the code that discovers the port that was
> actually bound and is not reporting that back correctly.
> 
> 
> Should be straight forward to do by debugging the function
> GDBRemoteCommunicationServerPlatform::Handle_qLaunchGDBServer(...) in
> GDBRemoteCommunicationServerPlatform.cpp and see what is going on and
> why it is returning 0 as the port.
> 
> Greg
> 
> > On Aug 23, 2017, at 9:44 AM, Hans Wennborg via lldb-dev <lldb-
> dev at lists.llvm.org> wrote:
> >
> > This was marked as an lldb 5.0.0 release blocker since it's a
> > regression from 4.0.1: https://bugs.llvm.org/show_bug.cgi?id=34183
> >
> > lldb-dev: Is there any interest in fixing this bug?
> >
> > On Fri, Aug 4, 2017 at 10:13 PM, Ramana via lldb-dev
> > <lldb-dev at lists.llvm.org> wrote:
> >> Hi,
> >>
> >> I am trying to remote debug ARM (linux) target from x86 (linux) host
> >> and I am getting the following error while trying to launch a process.
> >> The local debugging on ARM works.
> >>
> >> error: connect remote failed (invalid host:port specification:
> >> '10.10.2.3')
> >> error: process launch failed: invalid host:port specification: '10.10.2.3'
> >>
> >> It appears the above error is because the gdb-remote is returning the
> >> communication port as zero.
> >>
> >> <  36> send packet: $qLaunchGDBServer;host:svrlin249;#bb
> >> <  19> read packet: $pid:298;port:0;#bf
> >>
> >> What are the possible reasons for the above behavior from gdb-remote
> >> and how I could resolve this?
> >>
> >> If it helps, below is the full log.
> >>
> >> (lldb) log enable lldb comm
> >> (lldb) log enable gdb-remote packets
> >> (lldb) platform select remote-linux
> >>  Platform: remote-linux
> >> Connected: no
> >> (lldb) platform connect connect://10.10.2.3:500
> >> 0x915bd78 Communication::Communication (name = gdb-remote.client)
> >> 0x915bd78 Communication::Disconnect ()
> >> 0x915bd78 Communication::Disconnect ()
> >> 0x915bd78 Communication::Connect (url = connect://10.10.2.3:500)
> >> Socket::TcpConnect (host/port = 10.10.2.3:500) TCPSocket::Connect
> >> (host/port = 10.10.2.3:500)
> >> 0x915bd78 Communication::Write (src = 0xbfcb7433, src_len = 1)
> >> connection = 0x915f578
> >> 0x915f608 Socket::Write() (socket = 7, src = 0xbfcb7433, src_len = 1,
> >> flags = 0) => 1 (error = (null))
> >> <   1> send packet: +
> >> this = 0x0915BD78, dst = 0xBFCB53EC, dst_len = 8192, timeout = 10000
> >> us, connection = 0x0915F578
> >> 0x915bd78 Communication::Write (src = 0x916022c, src_len = 19)
> >> connection = 0x915f578
> >> 0x915f608 Socket::Write() (socket = 7, src = 0x916022c, src_len = 19,
> >> flags = 0) => 19 (error = (null))
> >> history[1] tid=0x7cbf <   1> send packet: +
> >> <  19> send packet: $QStartNoAckMode#b0 this = 0x0915BD78, dst =
> >> 0xBFCB51AC, dst_len = 8192, timeout = 6000000 us, connection =
> >> 0x0915F578
> >> 0x915f608 Socket::Read() (socket = 7, src = 0xbfcb51ac, src_len = 7,
> >> flags = 0) => 7 (error = (null))
> >> <   1> read packet: +
> >> <   6> read packet: $OK#9a
> >> 0x915bd78 Communication::Write (src = 0xbfcb50f3, src_len = 1)
> >> connection = 0x915f578
> >> 0x915f608 Socket::Write() (socket = 7, src = 0xbfcb50f3, src_len = 1,
> >> flags = 0) => 1 (error = (null))
> >> <   1> send packet: +
> >> 0x915bd78 Communication::Write (src = 0x9161ff4, src_len = 13)
> >> connection = 0x915f578
> >> 0x915f608 Socket::Write() (socket = 7, src = 0x9161ff4, src_len = 13,
> >> flags = 0) => 13 (error = (null)) <  13> send packet: $qHostInfo#9b
> >> this = 0x0915BD78, dst = 0xBFCB510C, dst_len = 8192, timeout =
> >> 1000000 us, connection = 0x0915F578
> >> 0x915f608 Socket::Read() (socket = 7, src = 0xbfcb510c, src_len =
> >> 316, flags = 0) => 316 (error = (null)) < 316> read packet:
> >>
> $triple:61726d2d2d6c696e75782d676e75656162696866;ptrsize:4;watchpoint
> >> _exceptions_received:before;endian:little;os_version:3.10.31;os_build
> >>
> :332e31302e33312d6c7473692d30323836312d6738303161343066;os_kernel:2
> 33
> >>
> 520534d5020467269204d61792031332031353a35383a3232204953542032303
> 136;h
> >> ostname:736f
> >> 63667067615f617272696135;#0a
> >> 0x915bd78 Communication::Write (src = 0x915fe9c, src_len = 18)
> >> connection = 0x915f578
> >> 0x915f608 Socket::Write() (socket = 7, src = 0x915fe9c, src_len = 18,
> >> flags = 0) => 18 (error = (null)) <  18> send packet:
> >> $qGetWorkingDir#91 this = 0x0915BD78, dst = 0xBFCB50FC, dst_len =
> >> 8192, timeout = 1000000 us, connection = 0x0915F578
> >> 0x915f608 Socket::Read() (socket = 7, src = 0xbfcb50fc, src_len = 24,
> >> flags = 0) => 24 (error = (null)) <  24> read packet:
> >> $2f686f6d652f726f6f74#4b
> >> 0x915bd78 Communication::Write (src = 0x915fe9c, src_len = 19)
> >> connection = 0x915f578
> >> 0x915f608 Socket::Write() (socket = 7, src = 0x915fe9c, src_len = 19,
> >> flags = 0) => 19 (error = (null)) <  19> send packet:
> >> $qQueryGDBServer#cb this = 0x0915BD78, dst = 0xBFCB531C, dst_len =
> >> 8192, timeout = 1000000 us, connection = 0x0915F578
> >> 0x915f608 Socket::Read() (socket = 7, src = 0xbfcb531c, src_len = 7,
> >> flags = 0) => 7 (error = (null))
> >> <   7> read packet: $E04#a9
> >>  Platform: remote-linux
> >>    Triple: arm-*-linux-gnueabihf
> >> OS Version: 3.10.31 (3.10.31-ltsi-02861-g801a40f)
> >>    Kernel: #5 SMP Fri May 13 15:58:22 IST 2016
> >>  Hostname: socfpga_arria5
> >> Connected: yes
> >> WorkingDir: /home/root
> >> (lldb) file main
> >> 0x915bd78 Communication::Write (src = 0x91638fc, src_len = 137)
> >> connection = 0x915f578
> >> 0x915f608 Socket::Write() (socket = 7, src = 0x91638fc, src_len =
> >> 137, flags = 0) => 137 (error = (null)) < 137> send packet:
> >>
> $qModuleInfo:2f686f6d652f72616d616e616e2f776f726b5f726f6f742f546f545f
> >>
> 6c6c64622f74657374732f6d61696e;61726d2d2d6c696e75782d656162696866#
> f1
> >> this = 0x0915BD78, dst = 0xBFCB172C, dst_len = 8192, timeout =
> >> 1000000 us, connection = 0x0915F578
> >> 0x915f608 Socket::Read() (socket = 7, src = 0xbfcb172c, src_len = 7,
> >> flags = 0) => 7 (error = (null))
> >> <   7> read packet: $E03#a8
> >> Current executable set to 'main' (arm).
> >> (lldb) b main
> >> Breakpoint 1: where = main`main + 4 at main.c:4, address = 0x000104a0
> >> (lldb) run
> >> 0x915bd78 Communication::Write (src = 0x917bae4, src_len = 36)
> >> connection = 0x915f578
> >> 0x915f608 Socket::Write() (socket = 7, src = 0x917bae4, src_len = 36,
> >> flags = 0) => 36 (error = (null)) <  36> send packet:
> >> $qLaunchGDBServer;host:svrlin249;#bb
> >> this = 0x0915BD78, dst = 0xBFCB4FDC, dst_len = 8192, timeout =
> >> 10000000 us, connection = 0x0915F578
> >> 0x915f608 Socket::Read() (socket = 7, src = 0xbfcb4fdc, src_len = 19,
> >> flags = 0) => 19 (error = (null)) <  19> read packet:
> >> $pid:298;port:0;#bf
> >> 0x92b0a84 Communication::Communication (name = process.stdio)
> >> 0x92b0d78 Communication::Communication (name = gdb-remote.client)
> >> 0x92b0a84 Communication::Disconnect () Socket::TcpConnect (host/port
> >> = 10.10.2.3) TCPSocket::Connect (host/port = 10.10.2.3)
> >> Socket::TcpConnect (host/port = 10.10.2.3) TCPSocket::Connect
> >> (host/port = 10.10.2.3) Socket::TcpConnect (host/port = 10.10.2.3)
> >> TCPSocket::Connect (host/port = 10.10.2.3) Socket::TcpConnect
> >> (host/port = 10.10.2.3) TCPSocket::Connect (host/port = 10.10.2.3)
> >> Socket::TcpConnect (host/port = 10.10.2.3) TCPSocket::Connect
> >> (host/port = 10.10.2.3) Socket::TcpConnect (host/port = 10.10.2.3)
> >> TCPSocket::Connect (host/port = 10.10.2.3) Socket::TcpConnect
> >> (host/port = 10.10.2.3) TCPSocket::Connect (host/port = 10.10.2.3)
> >> Socket::TcpConnect (host/port = 10.10.2.3) ..................
> >> ..................
> >> ..................
> >> TCPSocket::Connect (host/port = 10.10.2.3) Socket::TcpConnect
> >> (host/port = 10.10.2.3) TCPSocket::Connect (host/port = 10.10.2.3)
> >> Socket::TcpConnect (host/port = 10.10.2.3) TCPSocket::Connect
> >> (host/port = 10.10.2.3) Socket::TcpConnect (host/port = 10.10.2.3)
> >> TCPSocket::Connect (host/port = 10.10.2.3) Socket::TcpConnect
> >> (host/port = 10.10.2.3) TCPSocket::Connect (host/port = 10.10.2.3)
> >> Socket::TcpConnect (host/port = 10.10.2.3) TCPSocket::Connect
> >> (host/port = 10.10.2.3)
> >> error: connect remote failed (invalid host:port specification:
> >> '10.10.2.3')
> >> 0x915bd78 Communication::Write (src = 0x92b38c4, src_len = 27)
> >> connection = 0x915f578
> >> 0x915f608 Socket::Write() (socket = 7, src = 0x92b38c4, src_len = 27,
> >> flags = 0) => 27 (error = (null)) <  27> send packet:
> >> $qKillSpawnedProcess:298#8b this = 0x0915BD78, dst = 0xBFCB509C,
> >> dst_len = 8192, timeout = 1000000 us, connection = 0x0915F578
> >> 0x915f608 Socket::Read() (socket = 7, src = 0xbfcb509c, src_len = 7,
> >> flags = 0) => 7 (error = (null))
> >> <   7> read packet: $E0a#d6
> >> error: process launch failed: invalid host:port specification: '10.10.2.3'
> >> (lldb)
> >>
> >>
> >> Regards,
> >> Ramana
> >> _______________________________________________
> >> lldb-dev mailing list
> >> lldb-dev at lists.llvm.org
> >> http://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-dev
> > _______________________________________________
> > lldb-dev mailing list
> > lldb-dev at lists.llvm.org
> > http://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-dev
> 
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