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I took an OS class and wanted to learn more afterwards so I hacked together a small kernel mostly using info from the osdev wiki. I got decently far (managed to

I took an OS class and wanted to learn more afterwards so I hacked together a small kernel mostly using info from the osdev wiki. I got decently far (managed to have a shell running, had VIM running), but ran out of steam years ago (that and the code needing a massive amount of cleanup and auditing). So I misremembered (it's been 6+ years ago) but it was the AMD PCNET driver I wrote that triggered the crash, not E1000. Excuse the code quality, but the driver I wrote is located here: https://github.com/blanham/ChickenOS/blob/master/src/device/net/pcnet.c https://github.com/blanham/ChickenOS/blob/master/src/device/... (Note the comment about it not working in Virtualbox) Attempting to boot my kernel with that driver activated would cause a hard freeze of the host OS, requiring a hard reset of the host machine. I replicated this multiple times, in Virtualbox for both OSX and Windows. Thanks for actually replying instead of downvoting, I guess I shouldn't make off-the-cuff comments and then forget to follow-up until the next day.

exikyut 8y ago
Interesting. I've been eyeing OS development for a while myself. I have a few high-level ideas about kernel design, and a few years's worth of musings about good UX. I badly need to get on with spending a few years getting my feet wet with actual implementation details and such so I'm not just a pile of unorientated hot air though, haha. Armchair pontificating doesn't count for much. But anyway. Huh, a shell and Vim. (Alongside multiple architecture support and two filesystems.) That's reasonably developed-out. Not bad! Can totally understand the problem of running out of steam. (I think that might be why I've been so hesitant about diving in myself - want to pace things so they stay interesting for long enough, and don't want to make too many discouraging mistakes. A couple kernel architecture arguments doesn't produce a good filesystem, adequately future-proof UI model, good vertical "little detail" semantics, etc etc. A hard crash on multiple platforms? That's almost definitely a bug. Heh, I think all the downvoters might've made a bunch of incorrect presumptions there :) It might be mildly interesting to see if you can still trigger the crash with the latest version of VirtualBox. (I'd have a go but of course I have no repro details, or info on how to actually build everything for that matter.) Precedent has just been set on 0daying VB networking hardware, for what that's worth :P but there's also Project Zero (which will accept security vulnerabilities in any software, and imposes a 90-day deadline) if VB's own bug bounty thing proves unappealing. This is of course getting a bit ahead of testing/re-verification. I mention it because I'm now very curious to know if the bug is still there, but of course HN comments are not the right place for a [Y] :) It's impossible to say if recreating the test environment (host OS version(s), host VirtualBox version) would prove fruitful if the latest VB versions seem (...seem...) immune. Vulnerability research seems to be consist of a lot of "hmm, that seems like it might run a tiny bit slower on months with a Q in them if the computer is leaning 30° to the left at 2:14PM in the afternoon" and then staring at Hex-Rays for 3 months to ultimately prove that your crazy theory is in fact valid (literal example https://ramtin-amin.fr/#nvmedma; https://ramtin-amin.fr/#nvmedma; very similar example https://bugs.chromium.org/p/chromium/issues/detail?id=648971 https://bugs.chromium.org/p/chromium/issues/detail?id=648971 - "one byte overflow"!). In any case, I wouldn't mind getting some more details and seeing the CLUNK in action. It's interesting at face value. NB. About that nvmedma link - it took me about 4-5 rereads of that article and its prequel (https://ramtin-amin.fr/#nvmepcie https://ramtin-amin.fr/#nvmepcie) before the bigger picture started to click. (I also need to check my comments somewhat frequently - and then remember to also actually follow-up after seeing I have replies! Woops. Thanks for the reply!)

exikyut 8y ago

Interesting. I've been eyeing OS development for a while myself. I have a few high-level ideas about kernel design, and a few years's worth of musings about good UX. I badly need to get on with spending a few years getting my feet wet with actual implementation details and such so I'm not just a pile of unorientated hot air though, haha. Armchair pontificating doesn't count for much. But anyway. Huh, a shell and Vim. (Alongside multiple architecture support and two filesystems.) That's reasonably developed-out. Not bad! Can totally understand the problem of running out of steam. (I think that might be why I've been so hesitant about diving in myself - want to pace things so they stay interesting for long enough, and don't want to make too many discouraging mistakes. A couple kernel architecture arguments doesn't produce a good filesystem, adequately future-proof UI model, good vertical "little detail" semantics, etc etc. A hard crash on multiple platforms? That's almost definitely a bug. Heh, I think all the downvoters might've made a bunch of incorrect presumptions there :) It might be mildly interesting to see if you can still trigger the crash with the latest version of VirtualBox. (I'd have a go but of course I have no repro details, or info on how to actually build everything for that matter.) Precedent has just been set on 0daying VB networking hardware, for what that's worth :P but there's also Project Zero (which will accept security vulnerabilities in any software, and imposes a 90-day deadline) if VB's own bug bounty thing proves unappealing. This is of course getting a bit ahead of testing/re-verification. I mention it because I'm now very curious to know if the bug is still there, but of course HN comments are not the right place for a [Y] :) It's impossible to say if recreating the test environment (host OS version(s), host VirtualBox version) would prove fruitful if the latest VB versions seem (...seem...) immune. Vulnerability research seems to be consist of a lot of "hmm, that seems like it might run a tiny bit slower on months with a Q in them if the computer is leaning 30° to the left at 2:14PM in the afternoon" and then staring at Hex-Rays for 3 months to ultimately prove that your crazy theory is in fact valid (literal example https://ramtin-amin.fr/#nvmedma; https://ramtin-amin.fr/#nvmedma; very similar example https://bugs.chromium.org/p/chromium/issues/detail?id=648971 https://bugs.chromium.org/p/chromium/issues/detail?id=648971 - "one byte overflow"!). In any case, I wouldn't mind getting some more details and seeing the CLUNK in action. It's interesting at face value. NB. About that nvmedma link - it took me about 4-5 rereads of that article and its prequel (https://ramtin-amin.fr/#nvmepcie https://ramtin-amin.fr/#nvmepcie) before the bigger picture started to click. (I also need to check my comments somewhat frequently - and then remember to also actually follow-up after seeing I have replies! Woops. Thanks for the reply!)