restart -> "Can't attach LWP" + hang

restart -> "Can't attach LWP" + hang

[David L]

I just installed gdb 6.5 and tried to use checkpoint/restart.  After
entering restart and next, I got the message:

[New Thread -1210636064 (LWP 20892)]
Can't attach LWP 20892: Operation not permitted

I typed next again and gdb stopped responding.

What am I doing wrong?

Thanks!

              David

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Re: restart -> "Can't attach LWP" + hang

[Daniel Jacobowitz]

On Fri, Aug 25, 2006 at 08:41:59AM -0700, David L wrote:
> I just installed gdb 6.5 and tried to use checkpoint/restart.  After
> entering restart and next, I got the message:
> 
> [New Thread -1210636064 (LWP 20892)]
> Can't attach LWP 20892: Operation not permitted
> 
> I typed next again and gdb stopped responding.
> 
> What am I doing wrong?

Are you using a threaded program?  I'm pretty sure that doesn't work
(and I can't think of any way to make it work, either).

-- 
Daniel Jacobowitz
CodeSourcery

Re: restart -> "Can't attach LWP" + hang

[David L]

>On Fri, Aug 25, 2006 at 08:41:59AM -0700, David L wrote:
> > I just installed gdb 6.5 and tried to use checkpoint/restart.  After
> > entering restart and next, I got the message:
> >
> > [New Thread -1210636064 (LWP 20892)]
> > Can't attach LWP 20892: Operation not permitted
> >
> > I typed next again and gdb stopped responding.
> >
> > What am I doing wrong?
>
>Are you using a threaded program?  I'm pretty sure that doesn't work
>(and I can't think of any way to make it work, either).
>
Not intentionally, but I'm pretty sure a library I've linked to is
spawning a thread under the covers.  I'm not sure which one.
Below is a list of my dependencies.  In any case, could gdb
detect that it's multithreaded and prevent me from inserting
checkpoint or restarting?

Thanks...

               David

PS - Here are my library dependencies.  I think one of them
starts another thread in a C++ constructor or something.
Perhaps there is a way to avoid that if there is a single-threaded
option in the configuration for that library so I can use the
fancy new checkpoint feature.

       linux-gate.so.1 =>  (0xffffe000)
        libsqlite3.so.0 => /usr/lib/libsqlite3.so.0 (0x008fd000)
        libGLU.so.1 => /usr/lib/libGLU.so.1 (0x02396000)
        libGL.so.1 => /usr/lib/libGL.so.1 (0x02801000)
        libXmu.so.6 => /usr/lib/libXmu.so.6 (0x00dc8000)
        libX11.so.6 => /usr/lib/libX11.so.6 (0x007d6000)
        libtcl8.4.so => /usr/lib/libtcl8.4.so (0xb7e8b000)
        libtk8.4.so => /usr/lib/libtk8.4.so (0x009bf000)
        libdl.so.2 => /lib/libdl.so.2 (0x00784000)
        libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0xb7da0000)
        libm.so.6 => /lib/libm.so.6 (0x007a7000)
        libgcc_s.so.1 => /lib/libgcc_s.so.1 (0xb7d93000)
        libc.so.6 => /lib/libc.so.6 (0x0064f000)
        libXext.so.6 => /usr/lib/libXext.so.6 (0x008d5000)
        libXxf86vm.so.1 => /usr/lib/libXxf86vm.so.1 (0x07fe8000)
        libpthread.so.0 => /lib/libpthread.so.0 (0x008e7000)
        libdrm.so.2 => /usr/lib/libdrm.so.2 (0x07fef000)
        libXt.so.6 => /usr/lib/libXt.so.6 (0x0233b000)
        libSM.so.6 => /usr/lib/libSM.so.6 (0xb7d89000)
        libICE.so.6 => /usr/lib/libICE.so.6 (0xb7d6f000)
        libXau.so.6 => /usr/lib/libXau.so.6 (0x0079f000)
        libXdmcp.so.6 => /usr/lib/libXdmcp.so.6 (0x007ce000)
        /lib/ld-linux.so.2 (0x00632000)

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Re: restart -> "Can't attach LWP" + hang

[Daniel Jacobowitz]

On Fri, Aug 25, 2006 at 09:06:42AM -0700, David L wrote:
> Not intentionally, but I'm pretty sure a library I've linked to is
> spawning a thread under the covers.  I'm not sure which one.
> Below is a list of my dependencies.  In any case, could gdb
> detect that it's multithreaded and prevent me from inserting
> checkpoint or restarting?

Probably, though I don't know quite how.

-- 
Daniel Jacobowitz
CodeSourcery

Re: restart -> "Can't attach LWP" + hang

[Michael Snyder]

On Fri, 2006-08-25 at 12:30 -0400, Daniel Jacobowitz wrote:
> On Fri, Aug 25, 2006 at 09:06:42AM -0700, David L wrote:
> > Not intentionally, but I'm pretty sure a library I've linked to is
> > spawning a thread under the covers.  I'm not sure which one.
> > Below is a list of my dependencies.  In any case, could gdb
> > detect that it's multithreaded and prevent me from inserting
> > checkpoint or restarting?
> 
> Probably, though I don't know quite how.

It's a good idea, might be as simple as querying the 
internal gdb thread list.  Maybe a good first contribution
for David L?