[Mono-dev] Soft Debugger issues (can't suspend threads in wait_for_suspend)

[Virgile Bello]

Just as a small addition, to confirm what I said earlier concerning
situation with additional threads.

After adding 2 threads that don't actually call mono (simply register them
with mono_thread_attach(mono_get_root_domain())), I end up having:
"Waiting for 2(4) threads to suspend..." which mean 1 of the fully native
threads is also blocking it.

Maybe it can't detect well when threads are running in native mode?
I will continue to investigate as well.

On Wed, Jan 26, 2011 at 12:58 AM, Virgile Bello <virgile.bello at gmail.com>wrote:

> I am having trouble with mono soft debugger.
> - I embed Mono runtime in my program, and I got MonoDevelop to act as
> SoftDebugger client
> - Mono soft debugger is loading properly (first breakpoint usually works --
> if already set beforehand -- I can see callstacks, etc...)
> - As soon as I press F5 -- to execute until this breakpoint is reached
> again next iteration -- or if I disable/reenable this breakpoint, program
> hang (see log)
> - Main loop is in C and Mono functions are called regularly.
>
> I traced down the problem to thread(s) not suspending (cf log).
> Usually, it seems it is the Finalizer thread (in this case 00002054) that
> doesn't get suspended.
>
> In mono sources, I tried to call mono_gc_collect/mono_gc_invoke_finalizers
> in the suspend_thread loop. In that case, I can manage to have F5 working
> (breakpoint trigger every step inside the loop).
> However it doesn't work as soon as I do anything else (such as removing &
> adding again the breakpoint).
>
> I remember seeing this problem on more than 1 thread when I had other
> threads active (i.e. Waiting for 3(4) threads to suspend...)
>
> Does anyone have an idea? Maybe there is something special to do if Mono
> doesn't keep hand (often back to full unmanaged world since main loop is in
> C)
>
> Debugger log:
>  [00000410] Thread started, obj=04702F20, tls=004CDA60.
> [00000410] Suspended.
> [00000410] Resumed.
> [00000410] Suspending vm...
> [00000410] Sent event VM_START, suspend=2.
> [00000410] Suspended.
> [dbg] Agent thread started, pid=00001260
> [00002054] Thread started, obj=04702E70, tls=004EC1D8. < Finalizer thread
> [00002054] Suspended.
> [dbg] Received command VM(VERSION), id=1.
> [dbg] Received command VM(SET_PROTOCOL_VERSION), id=2.
> [dbg] Protocol version 2.2, client protocol version 2.2.
> [dbg] Received command APPDOMAIN(1), id=3.
> ...............
> [00000410] Suspended.
> [dbg] Received command TYPE(1), id=1785.
> [dbg] Received command TYPE(6), id=1786.
> [00002054] Received single step event for suspending.
> [00002054] Suspended.
> [dbg] Received command VM(RESUME), id=1787.
> [00001260] Resuming vm...
> [00002054] Resumed.
> [00000410] Resumed.
> [00000410] Suspending vm...
> [00000410] Interrupting 00002054...
> [00000410] Sent event TYPE_LOAD, suspend=2.
> [00000410] Suspended.
> [dbg] Received command TYPE(1), id=1788.
> [dbg] Received command TYPE(6), id=1789.
> [00002054] Received single step event for suspending.
> [00002054] Suspended.
> [dbg] Received command VM(RESUME), id=1790.
> [00001260] Resuming vm...
> [00002054] Resumed.
> [00000410] Resumed.
> [00000410] Suspending vm...
>  [00000410] Interrupting 00002054...
> [00000410] Sent event TYPE_LOAD, suspend=2.
> [00000410] Suspended.
> [dbg] Received command TYPE(1), id=1791.
> [dbg] Received command TYPE(6), id=1792.
> [dbg] Received command VM(RESUME), id=1793.
> [00002054] Received single step event for suspending.
> [00002054] Suspended.
> [00001260] Resuming vm...
> [00000410] Resumed.
> [00002054] Resumed.
> [00000410] Suspending vm...
> [00000410] Interrupting 00002054...
> [00000410] Sent event TYPE_LOAD, suspend=2.
> [00000410] Suspended.
> [dbg] Received command TYPE(1), id=1794.
> [dbg] Received command TYPE(6), id=1795.
> [dbg] Received command VM(RESUME), id=1796.
> [00001260] Resuming vm...
> [00000410] Resumed.
> [00000410] Breakpoint hit, method=Step, offset=0x1e.
> [00000410] Suspending vm...
> [00000410] Interrupting 00002054...
> [00000410] Sent event BREAKPOINT, suspend=2.
> [00000410] Suspended.
> [dbg] Received command VM(ALL_THREADS), id=1797.
> [dbg] Received command THREAD(1), id=1798.
> Waiting for 1(2) threads to suspend...
> Waiting for 1(2) threads to suspend...
> Waiting for 1(2) threads to suspend...
> Waiting for 1(2) threads to suspend...
> Waiting for 1(2) threads to suspend...
> Waiting for 1(2) threads to suspend...
> Waiting for 1(2) threads to suspend...
> Waiting for 1(2) threads to suspend...
> Waiting for 1(2) threads to suspend...
> Waiting for 1(2) threads to suspend...
>
>
>
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