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Complete loss of data and debugger crash after multiple restarts #303

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wk-952 opened this Issue May 20, 2015 · 11 comments

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@wk-952

wk-952 commented May 20, 2015

When debugging an application and restarting the process being debugged
many multiple times, the debugging data gets completely lost and the debugger eventually crashes.

When i re-open the debugger and attach the same application, the BPs and comments are completely lost, also another weird behavior is that some plugin files cannot be read.

Information thrown after crash:


Problem signature:
Problem Event Name: APPCRASH
Application Name: x32dbg.exe
Application Version: 0.0.2.5
Application Timestamp: 5550f014
Fault Module Name: QtGui4.dll
Fault Module Version: 4.8.6.0
Fault Module Timestamp: 55140866
Exception Code: c0000005
Exception Offset: 002ca6c0
OS Version: 6.3.9600.2.0.0.256.4
Locale ID: 1033
Additional Information 1: 5861
Additional Information 2: 5861822e1919d7c014bbb064c64908b2
Additional Information 3: d1d9
Additional Information 4: d1d94a13d3609d6b740644c12508f581


To reproduce this issue:
1- open/attach any application in the debugger,
2- restart this application more than 15-20 times (or even more, i can't really remember but it's
around this range).
** EDIT: got it, exactly after restarting 52 times! **

  • Don't restart it so fast, leave a second or two between each restart attempt,
    because if you kept pressing the restart button so fast, the debugger will eventually
    become unresponsive to all the debugging buttons (pause, stop, run, ...).
  • The number of restart attempts does not have to be necessarily after each other,
    this means you could be debugging an application for hours (and restarting it of course)
    and suddenly this happens, this is when the real pain occurs since all your work will be lost :(
  • Using latest snapshot from sourceforge (snapshot_2015-05-11_08-10)

This picture shows an example of the plugin file that couldn't be loaded
exactly before crash, even though it exist in the directory:
capture

@wk-952 wk-952 changed the title from Complete loss of data and debuuger crash after multiple restarts to Complete loss of data and debugger crash after multiple restarts May 20, 2015

@mrfearless

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mrfearless commented May 20, 2015

Does it occur when there are no plugins loaded, as in if you move / rename plugins folder and do the same restart x52? Would be able to narrow it down to x64dbg or a plugin resource exhaustion issue perhaps.

@wk-952

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wk-952 commented May 20, 2015

i tried that now, i've removed all the plugins, the databases and my custom UI settings
(colors and instructions spaces), so a completely clean installation,
then i loaded an application and placed a BP with a comment and tried again the restarting session,

but the same result :( after exactly 52 restarts the BP and the comment are gone,
this time the difference is that the debugger didn't crash,
so before closing it i added another BP and a comment and restarted the process (restart # 53)
and as i expected both the BP and the comment are gone.

i've actually tried the last 2 steps multiple times (i reached restart # 64) to make sure that any BPs and comments after that will always be deleted, and unfortunately yes that happens.

EDIT: another thing, i tried it now again and on restart # 52,
after the BP and the comment are gone, i kept restarting 4 or 5 more times, then i opened
the "db" folder and found the database file that corresponds to the application being
debugged still has all the information about the BP and the comment,
so i closed the debugger but immediately the ".dd32" file got deleted

@mrexodia

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mrexodia commented May 21, 2015

I always love those tests 😄 quite some time ago there was an issue with restarting more than two times. I will try to reproduce the crash after my exams...

A deleted file would be very strange though. I actually never modify the file, until a new one needs to be written. Maybe there is a very rare handle leak that overwrites the file or something.

@wk-952

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wk-952 commented May 21, 2015

I'll try it today or tomorrow with the build before the latest one from sourceforge (with and without plugins) to see if this issue was only introduced in the latest build or not.
wish you all the luck in your exams.

EDIT: unfortunately yes, it occurs with (snapshot_2015-05-08_04-36) too.

@mrexodia

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mrexodia commented Jun 6, 2015

probably this was fixed in 0c792c9

@mrexodia mrexodia closed this Jun 6, 2015

mrexodia added a commit that referenced this issue Jun 6, 2015

@wk-952

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wk-952 commented Jun 6, 2015

tried it now,
and the issue is still persistent :(

@mrexodia

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mrexodia commented Jun 16, 2015

freeze wasn't fixed. checking that now

@wk-952

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wk-952 commented Jun 16, 2015

reached restart attempt number 116 and no crashes happened 👍
but may i ask, what freeze ?!
i didn't have any freezes even after restart number 116 and when i closed the debugger it didn't hang

@mrexodia

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mrexodia commented Jun 16, 2015

If you restart very quickly (spam ctrl+f2) it will not respond to input
anymore.

On Tue, 16 Jun 2015 16:12 wk notifications@github.com wrote:

reached restart attempt #116 #116
and no crashes happened [image: 👍]
but may i ask, what freeze ?!
i didn't have any freezes even after restart #116
#116 and when i closed the
debugger it didn't hang


Reply to this email directly or view it on GitHub
#303 (comment).

@mrexodia

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mrexodia commented Jul 13, 2015

@wk-952 is this issue still present in the latest snapshot?

@wk-952

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wk-952 commented Jul 13, 2015

No, it was fixed, reached 77 restart attempts and there seems to be no problem.
Thank you very much, you can close this issue if you want.

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