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Joined 11 months ago
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Cake day: August 2nd, 2023

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  • An alternative definition: a real-time system is a system where the correctness of the computation depends on a deadline. For example, if I have a drone checking “with my current location + velocity will I crash into the wall in 5 seconds?”, the answer will be worthless if the system responds 10 seconds later.

    A real-time kernel is an operating system that makes it easier to build such systems. The main difference is that they offer lower latency than a usual OS for your one critical program. The OS will try to give that program as much priority as it wants (to the detriment of everything else) and immediately handle all signals ASAP (instead of coalescing/combining them to reduce overhead)

    Linux has real-time priority scheduling as an optional feature. Lowering latency does not always result in reduced overhead or higher throughout. This allows system builders to design RT systems (such as audio processing systems, robots, drones, etc) to utilize these features without annoying the hell out of everyone else.



  • Pretty sure expiry is handled by the local crowdsec daemon, so it should automatically revoke rules once a set time is reached.

    At least that’s the case with the iptables and nginx bouncers (4 hour ban for probing). I would assume that it’s the same for the cloudflare one.

    Alternatively, maybe look into running two bouncers (1 local, 1 CF)? The CF one filters out most bot traffic, and if some still get through then you block them locally?


  • I’ve recently moved from fail2ban to crowdsec. It’s nice and modular and seems to fit your use case: set up a http 404/rate-limit filter and a cloudflare bouncer to ban the IP address at the cloudflare level (instead of IPtables). Though I’m not sure if the cloudflare tunnel would complicate things.

    Another good thing about it is it has a crowd sourced IP reputation list. Too many blocks from other users = preemptive ban.


  • According to this post, the person involved exposed a different name at one point.

    https://boehs.org/node/everything-i-know-about-the-xz-backdoor

    Cheong is not a Pingyin name. It uses Romanization instead. Assuming that this isn’t a false trail (unlikely, why would you expose a fake name once instead of using it all the time?) that cuts out China (Mainland) and Singapore which use the Pingyin system. Or somebody has a time machine and grabbed this guy before 1956.

    Likely sources of the name would be a country/Chinese administrative zone that uses Chinese and Romanization. Which gives us Taiwan, Macau, or Hong Kong, all of which are in GMT+8. Note that two of these are technically under PRC control.

    Realistically I feel this is just a rogue attacker instead of a nation state. The probability of China 1. Hiring someone from these specific regions 2. Exposing a non-pinying full name once on purpose is extremely low. Why bother with this when you have plenty of graduates from Tsinghua in Beijing? Especially after so many people desperate for jobs after COVID.




  • StarDreamer@lemmy.blahaj.zonetoLinux@lemmy.mlHelp w/ crash
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    5 months ago

    Look at the line with the asm_exc_invalid_op. That seems like a hardware fault caused by an invalid asm instruction to me. Either something wrong is being interpreted as an opcode (unlikely) or maybe the driver was compiled with extensions not available on the current machine.

    OP, how old is your CPU? And how old is the nic you are using?

    Edit: did you use a custom driver for the NIC? I’m looking at the Linux src and rt_mutex_schedule does not exist. Nevermind. Was checking 4.18 instead of 6.7. found it now. The bug is most likely inside a macro called preempt_disable(). Unfortunately most of the functions are pretty heavily inlined and architecture dependent so you won’t get much out of it. But it is likely any changes you made in terms of premption might also be causing the bug.




  • Amazon Smile trades ad views for 1% of their proceeds to a non-profit of your choice (including the FSF, EFF, and more, though I think RMS would have a seizure accepting this money)

    Whole Foods gives you significant discounts on hot foods if you scan a QR code from the app (still expensive though).

    I don’t use these personally but I can totally see someone using them.








  • Is there a specific reason you’re looking at shadowsocks? The original developer has been MIA for years. People who used it in the past largely consider it insecure for its original stated purpose

    trojan-gfw is a better modern replacement. However that requires a certificate in order to work. You can easily get one via lets encrypt.

    At this point, let Shadowsocks, obfs, and kcp die a graceful death like GoAgent before it did.


  • I don’t think either of us is the target audience here. I can see a “cheaper” (questionable) Pro laptop being useful for students going into college with a limited budget. An undergrad CS/graphic design degree shouldn’t tax an 8gb machine too much, assuming students shut down everything else when doing their once-a-semester major rendering/compiling/model training. If people just want Macbook pro software with more ports, a “cheaper” machine is better than none. Personally, I would still get a used/refurbished machine though.

    That being said, my current laptop workload tends to be emacs, qpdfview, Firefox, and tmux on EL9. For the remaining stuff, I usually just spin up a VM then ssh/xrdp into it. As for slack, teams, jabber, etc, I’m happy to report I’ve been out of industry/IT for 1+ years and don’t plan on going back anytime soon. For all I care, Apple can call their models unicorn edition. As long as it sells it’s not stupid.