Re: ssh_handle_packets blocking issue

[Aris Adamantiadis <aris@xxxxxxxxxxxx>]

Hi Mikhail,

Does your problem still happen with 0.5 ? The network code was pretty
much rewritten, and I think that bug should have disappeard together
with the synchronous system.

I'll check again, because it may be something completely different now
that I read it. was this channel_read the *first* channel_read on the
channel ? Do the content of the buffer you're dumping the correct
content of your channel ? is it possible that it's some garbage or
similar content of another session/channel ?

If content is correct and buffer->used is null, there's indeed a problem.

Thanks,

Aris
Le 5/04/11 21:46, Mikhail Kulinich a écrit :
> Hello,
> 
> It seems that guys meet an issue which I am observing for a year or more.
> During migration to new bug tracker, that original issue (created by me)
> was missed.
> The latest info I sent to the mailing list concerning it:
> {{{
> #2  0x080e4138 in ssh_socket_unbuffered_read (s=0x8ca3eb0,
> buffer=0x8c9e1c8, len=16)
>     at /home/shamanin/libssh_lin/
> libssh-0.4.4/libssh/socket.c:200
> 200       rc = recv(s->fd,buffer, len, 0);
> Current language:  auto; currently c
> (gdb) up
> #3  0x080e430b in ssh_socket_completeread (s=0x8ca3eb0,
> buffer=0x8c9e1c8, len=16)
>     at /home/shamanin/libssh_lin/libssh-0.4.4/libssh/socket.c:275
> 275       while((r = ssh_socket_unbuffered_read(s, ((uint8_t*)buffer +
> total), toread))) {
> 
> 
>  (gdb) bt 
> #0  0xb776e424 in __kernel_vsyscall ()
> #1  0xb770a428 in recv () from /lib/tls/i686/cmov/libpthread.so.0
> #2  0x080e4138 in ssh_socket_unbuffered_read (s=0x8ca3eb0,
> buffer=0x8c9e1c8, len=16)
>     at /home/shamanin/libssh_lin/libssh-0.4.4/libssh/socket.c:200
> #3  0x080e430b in ssh_socket_completeread (s=0x8ca3eb0,
> buffer=0x8c9e1c8, len=16)
>     at /home/shamanin/libssh_lin/libssh-0.4.4/libssh/socket.c:275
> #4  0x080e4985 in ssh_socket_wait_for_data (s=0x8ca3eb0,
> session=0x8ca4c58, len=16)
>     at /home/shamanin/libssh_lin/libssh-0.4.4/libssh/socket.c:405
> #5  0x080e1e54 in packet_read2 (session=0x8ca4c58)
>     at /home/shamanin/libssh_lin/libssh-0.4.4/libssh/packet.c:94
> #6  0x080e2429 in packet_read (session=0x8ca4c58)
>     at /home/shamanin/libssh_lin/libssh-0.4.4/libssh/packet.c:401
> #7  0x080cdd56 in channel_read (channel=0x8ca9720, dest=0x8cad460,
> count=1, is_stderr=0)
>     at /home/shamanin/libssh_lin/libssh-0.4.4/libssh/channels.c:1916
> #8  0x0809958b in maux::SshDescriptor::read (this=0x8ca46d8,
> cpBuf=0x8cad460 "", iBufLen=1,
>     iFlag=0) at ../SshDescriptor.cc:415
> #9  0x08053e57 in autotest::SshAccess::_receive (this=0x8ca46d8,
> buffer=@0xb32b10a8)
>     at ../SshAccess.cc:177
> #10 0x080543ed in autotest::SshAccess::onActivity (this=0x8ca46d8,
> pWaiter=0x8ca4298, iFlags=1)
>     at ../SshAccess.cc:300
> #11 0x08092fd3 in maux::Waiter::onActivity (this=0x8ca4298,
> pxDescr=0x8ca46d8, iFlags=1)
>     at ../Waiter.cc:915
> #12 0x08093b7d in maux::Waiter::dispatchOneEvent (this=0x8ca4298) at
> ../Waiter.cc:692
> #13 0x08094992 in maux::Waiter::doMainLoop (this=0x8ca4298) at
> ../Waiter.cc:506
> #14 0x08096f04 in maux::OwnThread<maux::Waiter>::main (this=0x8ca42f4)
> at ../Thread.hh:183
> #15 0x08091afc in maux::mainThreadFunction (pxThreadStartup=0xb63f972c)
> at ../Thread.cc:40
> #16 0xb770350f in start_thread () from /lib/tls/i686/cmov/libpthread.so.0
> #17 0xb74f07ee in clone () from /lib/tls/i686/cmov/libc.so.6
> (gdb) up
> #4  0x080e4985 in ssh_socket_wait_for_data (s=0x8ca3eb0,
> session=0x8ca4c58, len=16)
>     at /home/shamanin/libssh_lin/libssh-0.4.4/libssh/socket.c:405
> 405         r = ssh_socket_completeread(session->socket,buf,to_read);
> (gdb) up
> #5  0x080e1e54 in packet_read2 (session=0x8ca4c58)
>     at /home/shamanin/libssh_lin/libssh-0.4.4/libssh/packet.c:94
> 94            rc = ssh_socket_wait_for_data(session->socket, session,
> blocksize);
> (gdb) up
> #6  0x080e2429 in packet_read (session=0x8ca4c58)
>     at /home/shamanin/libssh_lin/libssh-0.4.4/libssh/packet.c:401
> 401       return packet_read2(session);
> (gdb) up
> #7  0x080cdd56 in channel_read (channel=0x8ca9720, dest=0x8cad460,
> count=1, is_stderr=0)
>     at /home/shamanin/libssh_lin/libssh-0.4.4/libssh/channels.c:1916
> 1916        if ((packet_read(session)) != SSH_OK ||
> (gdb) print channel->stdout_buffer
> $1 = (ssh_buffer) 0x8ca8640
> (gdb) print channel->stdout_buffer->used
> $2 = 0
> (gdb) print *channel->stdout_buffer
> $3 = {
>   data = 0x8cacc58 "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<hello
> xmlns=\"urn:ietf:params:xml:ns:netconf:base:1.0\">\n<capabilities>\n<capability>urn:ietf:params:netconf:base:1.0</capability>\n<capability>urn:ietf:params:netc"...,
> used = 0, allocated = 2048, pos = 0}
> 
> }}}
> 
> If you need more details I'll try to get them.
> 
> 2011/4/5 Aris Adamantiadis <aris@xxxxxxxxxxxx <mailto:aris@xxxxxxxxxxxx>>
> 
>     Jeetu,
> 
>     I read your email in details and still am not sure it's correlated with
>     Sharon's problem.
>     Could you provide me a backtrace (with full symbols if possible) of a
>     stuck process (with the -1 timeout) so I can have an idea of what
>     condition it's waiting for and why it doesn't arrive.
> 
>     A verbose log (with ssh_options_set) of the same session would greatly
>     help, along with the code snippet you're using to handle ssh connexions.
> 
>     Thanks,
> 
>     Aris
> 
>     Le 5/04/11 14:20, jeetu.golani@xxxxxxxxx
>     <mailto:jeetu.golani@xxxxxxxxx> a écrit :
>     > Hi,
>     >
>     >> Hello Jeetu, Sharon,
>     >
>     >> I'll look at that issue asap. It's a blocking problem for release
>     0.5.
>     >
>     >> Aris
>     >
>     > Aris, Thanks so much :) Please let me know if you need me to try
>     something
>     > or any further data to help you debug this.
>     >
>     >> If this is on Windows, which Windows version are you running? We
>     have a
>     >> poll(2)-emulation for older Windows versions. This version
>     doesn't set
>     >> POLLERR, maybe that's causing the problem.
>     >>
>     >
>     > Andreas, I'm seeing this behaviour on Linux (debian testing).
>     Please let
>     > me know if you need any further info to debug this or if I can
>     help in any way.
>     >
>     > Thanks so much yet again for a very nice piece of work :)
>     >
>     > Bye for now
>     > Jeetu
>     >
>     > ebrain.in <http://ebrain.in> | Beehive Computing
>     > Discover and run software from any device around you.
>     >
> 
> 
> 
> 
> -- 
> Mikhail
>