Break after given hit count (glitch?)

[avengerx]

I read at https://help.x64dbg.com/en/latest/introduction/ConditionalBreakpoint.html that once a breakpoint is hit, independently of its condition evaluation, $breakpointcounter is incremented.

In fact, it does. But I'm seeing something strange when I place a breakpoint in, say, a long for loop.

• First, I let it run to get how many hits it gets before the debugged app crashes (condition 0). I get then 439.
• Then I set it to (hopefully) drop a few loops before it crashes, say 437: $breakpointcounter >= 437

And it nicely broke the execution the second run... I just can't really tell it was right, as now in Breakpoints tab, I read 1079 hits right after setting the new breakpoint condition!

If I let the program run again, then it really stops in the breakpoint, but the hit count says 1077. It's as if I reference $breakpointcounter in the condition, it increments itself again, or something, as it is not really just double, or a triple value!

Then I get confused and let it run until breaks again (condition 0 to never break) and the program reaches its defective code with hit count still 1079. If I set to 1077 or less, it would again break when the unhandled exception triggers.

Perhaps there's a more appropriate to break after the 437 hits?

[mrexodia]

[mrexodia]

Applications are not always deterministic, but you can put $breakpointcounter == .437 to break on the 437th hit.

[avengerx]

And then it comes back to the 439 being likely an hex value, 437 should be two behind it no matter what.
If I read the breakpoint say 439 hits and edit (shift+f2) asking it to stop at 437, upon save/closing the edit dialog, the breakpoint immediately reports 1077 hits.

Notwithstanding, if I re-run to the 437 hits (without heading dot) it does stop much much earlier (at least over 10 hits earlier, I stopped counting). So no matter how I look at it, it's not adding up. I'll have to do more checks to see if the program is behaving differently every time.

[avengerx]

If I read the breakpoint say 439 hits and edit (shift+f2) asking it to stop at 437, upon save/closing the edit dialog, the breakpoint immediately reports 1077 hits.

Just emphasizing this segment, that's what I meant.
Anyway, now I'm trying changing to breakif(0) and breakif($breakpointcounter >= .1500 (both that shouldn't break before the program crashes) and it no longer reports 439 hits on crash no matter how many times I restart the program. I might have hit some edge case I don't know how to reproduce. If I reproduce it again I'll update this.

[mrexodia]

Can you record a video showing what is going on? The displayed count should be in decimal and it’s a bit difficult to understand what is going on exactly…

[avengerx]

I couldn't reproduce this anymore; I am sure it happened and it was very strange. Then number of breakpoint hits changing a lot with the program paused somewhere (in the exception, in my case). If I can repro that, I'll try to isolate the cause and post an update here.