How Do Linux Kernel Drivers Work? - Learning Resource

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If you want to hack the Kernel, are interested in jailbreaks or just want to understand computers better, Linux Device Drivers is a great book to get you started. I used to learn the basics and in this video I want to share what clicked for me.
LDD Book: lwn.net/Kernel/LDD3/
LDD3 Example Code Updated: github.com/martinezjavier/ldd3
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Опубликовано:

19 июн 2024

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Комментарии : 607

@first-thoughtgiver-of-will2456 3 года назад

I remember my dad, an old school linux military man told me that writing drivers was the "initial task" of many linux programmers. Thank you for sharing your experience.

@wanglin1943 2 года назад

Most programmers are still writing applications, and a few engineers who write drivers usually work in semiconductor chip manufacturers

@psykjavier Год назад

@@wanglin1943 for example, an embedded linux engineer who works touching registers of the SOC. and making drivers for a user developer can use it without worry about the details of how to deal with that specific low level procedures.

@mithrandirthegrey7644 10 месяцев назад

It most definitely isn't and shouldn't be. Writing drivers is dangerous if you don't know what you're doing. The idea that some fresh graduate is writing linux drivers for military hardware is down right terrifying. Airplanes would be falling from the sky. No. You should be very comfortable in userspace before you ever venture down to the kernel and start touching hardware.

@crimsomnia1415 9 месяцев назад

@@mithrandirthegrey7644 I'll have to disagree with you there, though I understand where you're coming from. Certainly you shouldn't be trying to make robust computing systems from scratch if you've no idea what you're doing, but the best way to learn is by understanding the core principles first and then build a grasp of understanding more complex systems from there. The deeper you go into the files, systems and hardware, the simpler things become, and at the core of all computing lies nothing else but understanding the concept of "on" and "off". Building system drivers used to be something people with no computing background had to figure out themselves just by the instruction manual (this is how the security firm I work at had to do it when they first started introducing electrical equipment at the company). It's far harder to try and figure out why a projector doesn't work when you have no idea to begin with how it's even *supposed* to work. When you understand the basic principles it's much easier to infer where things might have gone awry.

@mithrandirthegrey7644 9 месяцев назад

@@crimsomnia1415 I don't disagree that writing hardware drivers is a great exercise for tinkerers and an excellent way to learn things like communication stacks and hardware flow. I vehemently disagree that a pimple faced engineer fresh out of college should be writing hardware drivers for military hardware. That sounds scary.

@davidalm2148 4 года назад

Hey @LiveOverflow Regarding 14:30; Python is internally calling the C the standard library's stdio buffered functions (fread/fwrite) which does the buffering which internally makes the syscall specifying the file descriptor, which triggers the char module's read/write function.

@krisavi 4 года назад

That is true, python is not very efficient code in that sense, but you get the ease of writing code. However for the example he could have done manual flush before closing. To show that you can force the write to disk without waiting for close or buffer to get full. Normally it gets buffer full until write happens to avoid excessive write operations on disk. It is all about optimizing operations and not to cause bunch of writes to take up CPU instructions while there is nothing to write. For such a small example it would have shown it maybe more how things work and even how close is doing the flush automatically doing it in a way more like open -> write -> flush -> write -> close. On windows on the other hand I have noticed that it does not respect flush always (more reliable on linux). There can be few cases where it does not even write to device, even if you call it to do it, I do not know all the specifics. Well nvm... Watched half a minute more and it was there already :D

@michaelandersson6088 4 года назад

Fun fact: Linux kernel v2.6 has ~8 million lines of code, v5 has ~26 million lines of code :)

@Zooiest 4 года назад

That’s... A lot... I coded a JS project for ~2 months a few hours per day and it has only 35k lines iirc

@Qizot 4 года назад

I still don't know how C code can be scaled to this amount

@ehmeth 4 года назад

Is this where I mention Casey Muratori's "The Thirty-Million Line Problem"?

@alexstone691 4 года назад

@@Qizot Imagine your worst nightmare but worse But for real C code becomes a mess, i understand why people use it but it feel like its a chore to start a project in c

@masonfuller9823 4 года назад

hol' up

@mrgummage 4 года назад

Thumbs up for LiveOverflow ASMR where he reads Linux Device Drivers (Third Edition).

@trickster1833 4 года назад

At the beginning, is that Ben Eater's 8-bit breadboard computer design?

@joris-rietveld 4 года назад

Haha I also recognized it, I am currently building my CPU logic but I burned some stuff so waiting for a delivery from china :-)

@ukaszMarianszki 4 года назад

Yeah, he is building it on streams

@shubham.1172 4 года назад

I built a similar one on Logisim! Do check it out github.com/shubham1172/SRM

@shubham.1172 3 года назад

@@zack3g aye, thanks! It would be amazing if we design some high level language for it 🤣

@youdonotknowmyname9663 3 года назад

@@shubham.1172 Logisim is awsome! And discrete computers are awsome!

@tiaanbasson9092 27 дней назад

Scott Pilgrim talks about Linux kernel drivers. Good video.

@roseproctor3177 2 года назад

your passion is great! I'm still a beginner programmer. I've taken one term of python and two terms of C++ in community college, so there is still a lot here that goes over my head, but it was really valuable to find this tutorial and explanation, and I can guarantee Ill probably revisit this video in the future as this is now a jumping off point to asking even better questions to understand what I need.

@tollertup 4 года назад

i Just followed the code example and was blown away. Great work. A lot of people say making a series out of that would be amazing and I can only agree!

@shire7949 4 года назад

Hey. I enjoyed the video. I didn't really feel it was 17 minutes long. It went by fast. Just wanted to say this might be a very good, and so far unimplemented type of video format: You pick a free-to-the-public book, like this one, and read/work through it chapter by chapter. Except you might do it in like a live-stream format ? (maybe one livestream per chapter) I know the live part is kinda daunting, but I feel that doing this would either way help you: - You get obviously the benefits from reading/working through the book. - I feel this might attract viewers since in a way, you will pretty much look like you are "noob" while learning. It will show the viewer that learning is a sort of tough process ? And that they shouldn't expect to know it all in one sitting. And in a way, since this actually attracts people, you might feel the freedom of messing up, of not editing, of not having to look too damn professional. Just be yourself, learning. - Get the profit from the views. - I don't know if this one counts but: Sometimes (really uncommon times), knowledgeable viewers might get in the livestream, so if you don't know a certain something, or are working through something they know, they might raise helpful ideas or explanations, thus increasing the dialog, making it more engaging to viewers to stay in the stream. I really wish you could do it with ANY book. Of course copyright :/ (I wonder if it's legal that you could buy the book, and then show it here. Or work through it this way) Maybe you could even do patreon requests every time you want a new book; effectively making us pay for it. Since in the end, you would be providing us with useful info. In the end. You might get a nice catalog of playlists of books you've worked through. Viewers from any point in time [who bought / are interested in a book] can follow along with you in the future. You put a bunch of ads in every live-stream, and PROFIT. Maybe it is nice publicity for the book ? and also for you. So that you can tweet or somehow contact the writers about doing copyright books. Maybe some will allow it? I know for instance there's this open book about reverse engineering, that the guy updates constantly, and he releases totally free. So you might work through it ? learn, and PROFIT. All while making the book more known, increasing the dialogue, etc.

@paulstelian97 4 года назад

That's actually a really good idea. Since this book is public, there probably wouldn't be any license issues, plus maybe the original authors could explicitly allow it if there was an issue.

@Xorume. 4 года назад

This is an awesome idea! I'd love to watch it.

@ara0n 4 года назад

This is a great idea

@TheNewton 4 года назад

We'll probably start seeing a format in the coming years for quite a number of reasons on top of the ones Shire Grin wrote about. A current example to observe is web development tutorials that heavily rely on the W3C standards docs as a reference but barely mention small parts of it across multiple videos often on one feature of the web standards specifications and actually reading of the full spec is left as an exercise to the reader but most developers never do to their detriment. Some other future predictions: * Barrier to entry to make long format video gets lower and lower due to proliferation of online video platforms and modern hardware * Higher job dissatisfaction, or outright unemployment, lower hours due to increasing automation for knowledge workers to have more free time, that ironically creates a catch-22 of more educational materials to make more knowledge workers to increase automation. * Streaming as a service/culture maturing as an viable industry for self-employment and socializing * The need for more and more content hours to get captive views * Creating longform content is hard to come up with let alone make; enter wikibooks,published papers, etc. * Rejection fatigue from the oversaturation of online "course" services * Students/learners using streaming socialization as a way to hold themselves accountable to learn something on a schedule in a culture that pushes for constant connection(human and network). And or using the recording as an notesystem. * Publishers are always looking for ways to sell more books so on the copyright side of things getting a teachers edition and a deal for content creators to make a streaming "course" of the book with presales of the book as a requirement of "attendance" or as a way to supplement MooC's which have waned in lieu of "course" platforms.

@hiitsrudd8567 4 года назад

Shire Grin, you nailed how this vid zoomed by, most YT vids are boring & have nothing to say in the end.

@robbingoossens 4 года назад

Mate, are you reading my search history or something? I've been searching for a good explanation of Linux kernel drivers for a couple of days now xD

@0xssff 4 года назад

Same lol, it all started with figuring out what the mknod command does...

@looploopertzg3511 4 года назад

Google youtube algorithm kindof sold your data...to him...but it's okay

@roshe7199 4 года назад

haha same!!

@BeHappyTo 4 года назад

reality is not

@HritikV 4 года назад

@@looploopertzg3511 We trust him !!

@delqyrus2619 4 года назад

I actually searched for something like this for quite a while and now i randomly stumble over it just by subscribing your channel! Thank you! That helps me so much with one of my projects!

@daumtto 2 года назад

Wow, really impressed by the explanation you've provided! I'm taking an embedded software course, and I really needed this!

@ih8tusernam3s 4 года назад

Thanks for all your help, been interested in reversing for years and have rarely found a more concise and comprehensive resource.

@solveit1304 4 года назад

This is mindblownig as you said! I never knew how that devices works and acting like a file - thanks for that daily videos, I'm learning so much stuff

@joonasfi 4 года назад

Great video! It is truly fascinating that one can compose these file and block drivers on top of each other so that a simple open+write to a certain file can go through a Samba client to send the write call to another server, have it written to an ext4 filesystem which uses a virtual block device which stacks in transparent encryption and mirroring to two different underlying disks, which are actually just block devices, or even might span multiple disks via again virtual block devices...

@DonEdward 4 года назад

Thanks for making this video explaining this book. I didn't make it very far! Now i get it more! Please consider going through more of this fascinating series!

@homere3931 4 года назад

how you went into the library to analyze the makefile, realized that you have that directory on your linux and then just executed it and it works was just amazing :D

@SciCynicalInventing 4 года назад

This is exactly what I was looking for as Im learning how to make my own kernel modules. Maybe you could expand on building makefiles and cross compiling things as is frequently done when working with embedded linux systems. Great video!

@DantalionNl 4 года назад

That is so awesome, I have read tried to read this book in the past but never got far because the examples did not work anymore. Thank you for this video and providing this resource tons of fun writing my own drivers to be had now :)

@adammontgomery7980 4 года назад

Awesome video, I did the simple hello kernel module a few years ago and was in over my head. I wanted to create a simple way to send commands to an Arduino, ultimately controlling a stepper motor. I thought the best way to do that would be to create a driver and simple "client-side" code to take commands in the terminal, writing to the device "file" to provide a number of steps and direction to the stepper motor. You've re-ignited my interest and I may make another attempt.

@akasshjoshhi6926 4 года назад

My University exams just ended for now. I was wondering what should I learn and bam notification for this video appeared. Thanks for dropping this awesome resource man!

@jordanc.m.6735 4 года назад

Your enthusiasm is contagious

@GorczakWiktor 4 года назад

I'm really glad to have found this channel. Extremely interesting, very straight-foward and substantive :)

@soapmcsoaperson 4 года назад

Hell of a nice coincidence, I had just started reading the first chapter of this book. Thanks for the vid, man

@geodome83 4 года назад

creepy social media tracking

@alexscarbro796 4 года назад

This is a very good book and truly insightful. I used it to start writing a driver for a PCIe based FPGA development board.

@cern1999sb 4 года назад

My 3rd year computer science project for my university course will require me to write Linux device drivers. This looks like a really good place to start. Thanks so much!

@DipanjanPatra 4 года назад

This is one of the most awesome videos to get started with kernel programming! Thanks for this one.

@martipk 4 года назад

i just finished studying this material this semester, and this was spot on, great video!

@martipk 3 года назад

@MichaelKingsfordGray what?

@cBake0 4 года назад

This was paradigm shifting for me :), been trying to grok device programming for a long time. Though admittedly never focused heavily on the subject, just pieces here and there. Thanks for the video

@_framedlife 4 года назад

I now want a 2hr version of this 😂 this was amazing

@filipsworks 4 года назад

Knew about linux drivers and fs devs a long before this video but to see an actual example... Exceptional! Thank You!

@tonyfremont 3 года назад

I have the first edition of this book, and the "Understanding the Linux Kernel". Those books, starting with Linux in 1994 and reading literally hundreds of Howto documents, and doing a Linux from scratch build, taught me a ton. Too bad that pretty much all of what I learned back then has since been superceded by evolution. Getting X up and running in the 90s was also a major learning experience.

@PhoenixClank 4 года назад

This is easy enough for me to understand, but still amazing enough to blow my mind.

@marekunas 4 года назад

How Linux Works, 2nd Edition: What Every Superuser Should Know by Brian Ward, also a great book regarding an overview of Linux.

@nikhilt3755 4 года назад

yeah i am reading that from few weeks and about to comment that book in this section GREAT BOOK

@0xssff 4 года назад

Got any more recommendations?

@nikhilt3755 4 года назад

@@0xssff Linux bible

@nikhilt3755 4 года назад

linux programming interface book

@nikhilt3755 4 года назад

ARCH WIKI this is a website where u can learn a lot

@talhadeniz8465 4 года назад

I love watching tutorial videos with more applicable examples like that. Better than useless entertainment videos.

@pdigit010 3 года назад

When I saw the cover of the book I thought it looked familiar.. and guess what I actually still have the printed version and had used it over 15 year ago! Happily surprised to see how younger generations and youtubers are enjoying hacking into the kernel avoiding to just use latest frameworks! Thanks for the video (and to the g recommendation system that made me bump into it!) :)

@michalsebek2089 4 года назад

Wow, it's so interesting. I always love getting known about how all the things, which were always magic to me, work and how they're connected with each other. Then, everything (some of the magic) clears out to me. I really like that feeling. Thank you.

@S1ckB0y 4 года назад

Thanks for making learning complex stuff enjoyable! Keep it up!

@neetpbg4 4 года назад

Dude, your enthusiasm is contagious. Nice vid, keep it up!

@wanglin1943 2 года назад

I have a certain understanding of drivers, and I have worked in semiconductor manufacturers before. This video is a driver getting started video. The reason I like this video is that the English pronunciation of the video owner is clearer and I can understand it better, which helps me practice English well.

@burntt999 3 месяца назад

Omg I’m so pumped up to go back to this book.. you helped me significantly on this!!

@ArthurStomp 3 года назад

Nice introduction! I enjoy videos about what happens under the hood on linux, specially when they are done in such smooth way

@shubhamchidrawar9477 3 года назад

Really enjoyed the video... It would be great to have a series of videos for all three types of LDD.

@rikilshah 4 года назад

Thanks for the very simple explanation of such a complex topic!

@psp.youtube 4 года назад

this is soo cool, what an awesome kickstarter for writing LDD's

@Nik__._. 2 года назад

Well, i'm a bit late to the party but this video gave me exactly the missing link I needed to connect some stuff in may thoughts! :) Thank you! Might as well try writing something now.

@RoiEXLab 4 года назад

Honestly this is probably one of the most interesting videos I watched from you so far. I mean the hacking videos are great too, but I never felt so enlightened 😱

@esaieledouxnjongssikouam9326 3 года назад

Ohh... very Nice .... but i have a problem .... My lib/modules/.../build doesn't exist...🤤🤤🤤😭😭😭 So i can't modify, create or unload some modules... Please can you help me...!??

@nikhilchouhan1802 Год назад

@@esaieledouxnjongssikouam9326 You entered the correct kernel version right?

@esaieledouxnjongssikouam9326 Год назад

@@nikhilchouhan1802 yeah

@1889990 4 года назад

Video starts. Me: I'm not sure if he can keep up the high quality of his videos with daily uploads. Also Me 3 Minutes later: Oh damn thats so interesting and well put together. Keep up the good work! I never regret watching a video of yours!

@NunoLopes99 4 года назад

Your passion is contagious!

@blackmennewstyle 4 года назад

I really enjoy his extreme enthusiasm

@danihp9238 4 года назад

Your passion is a font of inspiration for me, hope you can do more content about kernel development

@uthoshantm 4 года назад

Beautiful overview. Thanks!

@marindraganov8765 3 года назад

I do like your enthusiasm when you saw your code running in the kernel! LOL!

@TheBodgybrothers 4 года назад

Awesome! Best rundown on kmods ever.

@1314zerosktr 2 года назад

Really appreciate the book link, been looking for something like this

@damnoish 4 года назад

i wanted to hit the like at least 4 times while watching. would love more of this. thanks.

@matiitpl 4 года назад

why am I just seeing this now?! Amazing video and your enthusiasm :) love it

@tonysu8860 4 года назад

A bit different than what I expected based on the video''s title... This really doesn't describe or expand on kernel drivers, But as described in the opening minutes the driver interface provides a way to access, manipulate and even write code that can operate against kernel functions. In other words, the kernel driver isn't the real topic of this video but is a sideshow means to the real topic...accessing the kernel. So, although I felt I was misled, This video is still very interesting, educational, clear and well made. Kudos, I think many people can benefit from this.

@richtourist 4 года назад

Fantastic video, really enjoy your stuff. The joy in your eyes is great to see.

@VideosfromNH 3 года назад

Nice. I've been meaning to learn about device drivers. This video and the free book is just what I need to get started.

@mavhunter8753 4 года назад

I remember reading this book a few years back. It really is great.

@sandman0829 2 года назад

Such a great and extraordinarily helpful video, for less than 20 mins. Thanks :)

@motohisamoriya2136 3 года назад

I wrote the first Linux kernel device driver for the Linux version 2.4.5, SH -3 (Renesas 7709 and 7727) device drivers. I remember compiling and building many times. In Kernel space, there was no convenient crt0 that called the main function, so it was pretty hard. Before that, I had to fix the device drivers for FreeBSD 2.2, but they were completely different, so I had a hard time. The device driver is basically OK if read, write, ioctrl are implemented. As for interrupts, the handler is not too hard to figure out how the interrupt is occurring, but if you didn't follow kmalloc, kfree in that order, it immediately went out of control.

@arnonymous7211 4 года назад

your current video output is insane while maintaining and improving quality. big up bro

@burntt999 3 месяца назад

Holy crap… I tried to read this book years ago but was over my head…you just cleared some shit up for me! Bless you sir

@linhorse4405 4 года назад

I really like your 'File' gesture!

@MikaelFangel 4 года назад

Thanks for sharing! I'm learning a lot when watching your videos.

@MB-rc8ie 4 года назад

Wow, I am just now doing a course about writing device drivers with a project at my university, that may be useful, thanks

@msthalamus2172 3 года назад

I just spent the last few weeks in WDM hell, but I'd never seen Linux driver code before. It's so amazing how much simpler Linux driver code is than the equivalent in Windows!

@kfqfguoqf 4 года назад

Thank you so much for the channel, I keep learning a lot!

@pushkar260 4 года назад

Daily liveoverflow videos... cool!

@nashaut7635 4 года назад

If you like Python programming and file interfaces, you might love Python Fuse ( _pip install fuse-python_ ) : write a virtual file interface in Python, straighter to the goal without compiling kernel modules. Thanks a lot for this tutorial. Love it!

@osamazaid25 4 года назад

What a video 👏🏻 Awesome Job brother

@lookback6314 Год назад

Appreciate your hard work, and love your passion 👍

@peterfiser 4 года назад

Wonderful video, thank you. Editing was done superbly too. I hope you will have a proper office chair one day. That one looks painful to sit on.

@MusikSony 4 года назад

Nice video ! I´d love to see doing you a whole driver..

@KupriyanovKirill 3 года назад

Man, you give me so much inspiration!

@memoriasIT 4 года назад

Funny that I was just reading about this haha Great video, this book is definitely awesome

@Dahaksha 4 года назад

same xD

@konnosgar 8 месяцев назад

Amazing ! Really enlightening, like you said. Thank you so much!

@entropy79 3 года назад

Beautiful explanation. Thanks !!

@trakeC 3 года назад

Dude i was just thinking i should learn more about this and this video popped up. Thnx m8

@jared9190 4 года назад

You're a great teacher, keep it up!

@zoomer1468 4 года назад

Thats gold! Thank you for sharing that resources

@MrJackyieman 4 года назад

awesome vid! very clearly and simple

@MidnightAhri 4 года назад

This actually makes a lot of sense tbh, thx for the video ^~^

@codingmarco 4 года назад

Echt cooles Video! Studiere auch gerade Informationstechnik ander DHBW, allerdings mit Keysight. Ich wünschte es gäbe mehr Leute, die bei "Our code was executed" so begeistert sind... ;)

@nztuber 4 года назад

Great stuff. Very clear, thank you.

@ericgorder1 3 года назад

Awesome, now Linux drivers looks fun! Thanks for posting!

@kirancs6217 3 года назад

Many thanks and high appreciated for your enthusiasm, helping and flowing the knowledge river.please continue this great tech sharings

@russelljazzbeck 3 года назад

What a great video, i love your enthusiasm. Thanks!

@damonzh588 3 года назад

it's an guide for one want to dive into the kernel. before this i didn't know device driver is a good start point. anyway thank you for introduce this book.

@ThePituLegend 4 года назад

I just ended a course on Character Devices... I needed this video three months ago, not now!!! Jk, good video :)

@tactileslut 3 года назад

Am I wrong to pronounce 'char' as "care", as in character?

@Locost59 3 года назад

Great little video, thanks.

@jpierce2l33t 2 года назад

Very informative like all your videos, plus I got a good laugh when you flailed your arms around while saying 'and then, kernel magic happened' LOL

@salimibrohimi9813 4 года назад

I enjoyed this video so much. Thank you!

@mohamedabdelkhalek4298 4 года назад

This cool content when u grap a book and look into it like that or more to do a series whene u read book and explain it

@dipi71 4 года назад

This is excellent, and it really makes me want to write a driver - like way back after I purchased the 2nd edition of that »Linux Kernel Drivers« tome (for €39.60, ouch). Grüße aus Nürnberg (where IBM also has a building, near the Saturnweg)!