Re: Crash noticed multiple times using libssh 0.3.4

[Uday Tennety <uday.tennety@xxxxxxxxxxxxxx>]

Thanks Aris for investigating the issue and providing the fix. I'll test 
using this patch and let you know.

Thanks,
Uday.

Aris Adamantiadis wrote:
> I was too quick, I found the issue. I'll commit it in the 0.3 branch ASAP.
>
> Aris
>
> Aris Adamantiadis a écrit :
>   
> > Hello Uday,
> >
> > I think I found the source of the problem. Somewhere in the
> > enter_function() or leave_function(), a counter is underflowed (the
> > current indentation level). Could you test the attached patch ? It
> > doesn't resolve the indentation problem but stop it from crashing the
> > process. Seeing your log, it seem the problem is in ssh_connect_host.
> >
> > Thanks for your feedback, if the patch is helping, we'll commit it.
> >
> > Regards,
> >
> > Aris
> >
> > Uday Tennety a écrit :
> >     
> > > Hello Aris,
> > > I made changes to our code and added mutex for the read and write blocks
> > > for a particular session. During my testing, I still see the libssh
> > > crashing at times. Also, I found that it always crashes at the following
> > > location:
> > > A call to the function ssh_log() is made from function ssh_connect in
> > > client.c  Could it be that the session is getting corrupted at some
> > > point? Can you give me some pointers looking at this Log.
> > >
> > > Thanks for your help.
> > > Uday.
> > >
> > > t@133 (l@133) terminated by signal ABRT (Abort)
> > > 0xff2c16e8: __lwp_kill+0x0008:  bcc,a,pt  %icc,__lwp_kill+0x18  !
> > > 0xff2c16f8
> > > Current function is ssh_log
> > >   67         memset(indent, ' ', min);
> > > --------------------------------------------------
> > >
> > > current thread: t@133
> > >  [1] __lwp_kill(0x0, 0x6, 0x0, 0x6, 0xfc00, 0x0), at 0xff2c16e8
> > >  [2] raise(0x6, 0x0, 0xff2a4d28, 0xffffffff, 0xff2e8298, 0x6), at
> > > 0xff25ff38
> > >  [3] abort(0x2d740, 0x1, 0xfeb00ab0, 0xa8244, 0xff2eb298, 0x0), at
> > > 0xff240158
> > >  [4] os::abort(0x1, 0xfedca58c, 0x1, 0xfedb2000, 0x1858c, 0x18400), at
> > > 0xfeaf67b4
> > >  [5] VMError::report_and_die(0xfeded4a8, 0x0, 0x1, 0xfed6095b,
> > > 0xfed67006, 0xfedf2ce8), at 0xfec088d8
> > >  [6] JVM_handle_solaris_signal(0xb, 0xdec7d670, 0xdec7d3b8, 0xafc00,
> > > 0x0, 0x0), at 0xfe5b91e8
> > >  [7] __sighndlr(0xb, 0xdec7d670, 0xdec7d3b8, 0xfe5b8724, 0x0, 0x1), at
> > > 0xff2c0620
> > >  ---- called from signal handler with signal 11 (SIGSEGV) ------
> > >  [8] _memset(0xdec7d758, 0x20202020, 0xffffffd7, 0x17, 0xffffd740,
> > > 0xdec80000), at 0xff351040
> > > =>[9] ssh_log(session = 0x20202020, verbosity = 538976288, format =
> > > 0x20202020 "<bad address 0x20202020>", ...), line 67 in "log.c"
> > >  [10] ssh_connect(session = 0x20202020), line 510 in "client.c"
> > >
> > >
> > >
> > >
> > >
> > > Uday Tennety wrote:
> > >       
> > > > Hello Aris,
> > > > Thanks for your inputs. I'll make the changes to my code adding mutex
> > > > and let you know if I see any issues.
> > > >
> > > > Thanks,
> > > > Uday.
> > > >
> > > > Aris Adamantiadis wrote:
> > > >         
> > > > > ouch that reply-to catches me every time...
> > > > >  
> > > > > ------------------------------------------------------------------------
> > > > >
> > > > > Subject:
> > > > > Re: [Fwd: Re: Crash noticed multiple times using libssh 0.3.4]
> > > > > From:
> > > > > Aris Adamantiadis <aris@xxxxxxxxxxxx>
> > > > > Date:
> > > > > Tue, 19 Jan 2010 09:56:01 +0100
> > > > > To:
> > > > > uday.tennety@xxxxxxxxxxxxxx
> > > > >
> > > > > To:
> > > > > uday.tennety@xxxxxxxxxxxxxx
> > > > >
> > > > >
> > > > > Uday Tennety a écrit :
> > > > >  
> > > > >           
> > > > > > Hello Aris,
> > > > > > I tried initialization using ssh_init() before calling any of the ssh
> > > > > > functions but I still notice the crash. I've attached the relevant log
> > > > > > statements. We're actually using one thread to read from the channel
> > > > > > and
> > > > > > another thread to write. Do you think this might be the reason for the
> > > > > > crash? If so, what kind of workarounds do you recommend?
> > > > > >
> > > > > >     
> > > > > >             
> > > > > Hi Uday,
> > > > >
> > > > > I still have to analyze the log you provided, but by what you describe,
> > > > > the problem is that you're using two libssh function at same time on
> > > > > functions that are not threadsafe on the same channel.
> > > > >
> > > > > I would recommend the use of a mutex in your own code, in order to
> > > > > access only one libssh function at a time (at least on a single session,
> > > > > there is normally no problem on different sessions).
> > > > >
> > > > > Do not hesitate to ask if you need any help.
> > > > >
> > > > > Regards,
> > > > >
> > > > > Aris
> > > > >
> > > > >   
> > > > >           
>
>