6 ms·
DLL that was not present in memory despite not being formally unloaded
- defrost 4mo agoThat's some doggedly determined back tracing to uncover an unexpected heisenbug (loose meaning). So a total of 46% of the crashes were due to this rogue force-unload of a DLL. This is a case of bucket spray, where a single underlying cause generates a large number of different types of crashes.
- chrisjj 4mo agoWe've not yet seen sufficient evidence this is any type of heisenbug.
- zabzonk 4mo ago> The good news for the shell32 team is that they are off the hook; they are the victim. The bad news is that we don’t know who the culprit is. The story of software development through the ages.
- brookst 4mo agoWhen you’ve eliminated all possible explanation, it’s time to pack it in.
- taneq 4mo agoOh man, my journey from idealistic “there is always an explanation” youth to “some days it do be like that, and we may never know why” in a nutshell.
- jamesfinlayson 4mo agoYeah I'm nearly 15 years into my career and still once or twice a year I have a moment where I think - there is no way that should ever have worked and I really don't know why it ever worked and didn't cause any issues.
- zabzonk 4mo agoOr, as the original article suggests, blame someone else.
- masfuerte 4mo agoPart two: https://devblogs.microsoft.com/oldnewthing/20260626-00/?p=112472 https://devblogs.microsoft.com/oldnewthing/20260626-00/?p=11...
- Someone1234 4mo agoPart 1 was interesting; it isn't clear why he split that into a Part 2 since it adds little to the story and is a paragraph long.
- taneq 4mo agoMight have been an “I need to look into this” segueing into “ never mind”?
- londons_explore 4mo agoI assume the fact it is a third party application means debugging gets harder, and the business case for doing so is weaker/none. But I would hope that some kind of reverse debugger triggered on one of these crashes would make it pretty simple to say "who wrote this 01".
- microgpt 4mo agoYou could also look at modules loaded into all of those processes that crashed this way.
- garaetjjte 4mo agoYou usually hope that TTD points to the culprit in such situations. But once I encountered single-byte corruption that didn't make any sense in TTD trace, there was good value at write and next read was garbage. I never discovered whether that was CPU bug, corruption by GPU shaders, stray kernel writes, or whatever.(I think it's unlikely that CPU bug would manifest with both native and TTD-instrumented runs. Corrupted byte was inside heap allocated memory so it shouldn't be in GPU pagetables at all. Kernel writes wouldn't appear in TTD trace, so really I think that was most likely issue, but how to debug that...)
- kumarvvr 4mo agoI see posts like this, this deep dive into the call stacks and am always humbled and reminded of the limits of my knowledge about computers and programs.
- Panzer04 4mo agoNot a programmer?
- kumarvvr 4mo agoI am, for 20 years now. I do embedded stuff too. Still.
- Panzer04 4mo agoI'm a bit surprised you don't run into things like this then :). Do you use GDB and the like at all? Or do you mean all the windows specific stuff etc, I guess I was more imaging the call stack etc. No insult was intended XD
- kumarvvr 4mo agoI have done everything from desktop apps to web apps and a bunch in between. Regular debugging is good enough for me. Never had the need to go down into call stack level. Even with embedded programming, regular C debugger has always been enough.
- FartyMcFarter 4mo agoAs someone who has debugged his fair share of tricky low-level issues, the parts that I find impressive in his blog posts are things such as "then we look at the bytes in memory and oh yeah, this looks like an exception record". I would usually not think to do that (or be able to recognise it as easily as I presume he did).
- Chu4eeno 4mo ago
- rwmj 4mo agoWhat MSFT support policy do you need to have the legendary Raymond Chen take a look at it? I say this because we've reported a bunch of Windows bugs (mainly running Windows under virtualization) and getting them to pay attention at all is an up-hill battle.
- hackyhacky 4mo ago> What MSFT support policy do you need to have the legendary Raymond Chen take a look at it? If you have to ask, you can't afford it.
- DANmode 4mo agoPerhaps it’s a matter of subjective interest! Often that’s how these things go.
- xmodem 4mo agoIf you can reproduce it reliably and doing so generates some form of telemetry, then just set up some automation to keep doing that in a loop. From as many machines as possible. No comment is offered on if I have ever gotten a bug noticed this way.
- nopurpose 4mo agoHow big and important third-party vendor must be for Raymond Chen to dissect its coredumps?
- FartyMcFarter 4mo agoGiven his seniority, it could also be that he picks whatever bugs he wants to work on. Whether that is from personal interest, frequency of crashes or any other criteria. When you're at that level in a company, it's rare that someone would be micromanaging what you work on at all times.
- 1970-01-01 4mo ago>I asked for the 100 most recent crashes in that third party program and put them into a pivot table so I could see the distribution. Always wondered if crash reporting is some kind of shady business. It's good to know it does, at minimum, do what it promises and give valuable crash data to MS.
- DANmode 4mo agoShady, as in, where does that data end up after MS collects it, and why?
- hackrmn 4mo agoThe fact that Raymond Chen is debugging these kind of issues, tells me Microsoft is short on staff that has his particular set of skills, handing him the hairiest issues from the annals of Windows. The new hires are probably all about .NET and JavaScript and what have you -- whatever Microsoft is about these days. I doubt it's C/C++. Chen is probably on standby and is paid handsomely as a de-facto VIP consultant. He is a legend, but he's becoming somewhat of a vintage developer.
- deleted 4mo ago[deleted]
- forestry 4mo agoManaged dump analysis in windbg was a thing. It’s been many years since I’ve needed it, though. Service telemetry improved quickly thereafter.
- algorithmsRcool 4mo agoIt is still a thing, just not a very common one since the debugger in VS has become more ergonomic and powerful. But windbg is still the king here, for the most advanced analysis of both managed and unmanaged code and it isn't even close to be honest once you learn the arcane commands and incatations
- kjellsbells 4mo agoI do wonder how Microsoft will manage the transition of the NT generation. Raymond Chen has been doing this kind of work for thirty years. He probably has, what, another ten years, max? Who are the next generation of Windows gurus that will take up the mantle? Hanselman is good on the blog part, but not in Chen's class re Windows domain expertise. And Windows is not, despite all that is said, going away anytime soon. I think this could be a real problem. Hopefully there is a set of 25 year old developers in the Windows team who have deep and growing skills in Winternals, and Microsoft have the good sense to encourage them in their career.
- 4mo ago
- IChooseY0u 4mo agoWindows COM is super weird and way over engineered.
- rpeden 4mo agoI actually think COM is an amazing bit of engineering considering its intended use case. It still feels like a much more advanced way of sharing compiled libraries between different languages than the current default of "export a C ABI and communicate across the barrier via primitive sticks and stones." COM isn't perfect but I still find it impressive especially since COM/OLE are 40 years old at this point.
- microgpt 4mo agoIt basically is that. It's a standardized sticks and stones. Plus objects for some reason. But I don't think the objects are a bad thing - it allows multiple implementations of sometimes to co-exist - consider using two different GPUs from different vendors at the same time. It took a really long time and a bunch of hacks to make OpenGL support that, but DirectX could always do it (at least at the API level) by just creating two different ID3DDevice objects backed by different code from different DLLs both loaded at the same time. OpenGL basically loads the GPU driver DLL that directly implements the OpenGL functions while Direct3D uses a COM object with a vtable so it can easily have two different ones.
- antonvs 4mo ago[flagged]
- robocat 4mo agoClaude said: pass this one up to Raymond