[help] How to test kernel code that I wrote?
Hi everyone, I'm now reading *Unreliable Guide To Locking* which came from kernelnewbies.org (https://kernelnewbies.org/Documents/Kernel-Docbooks) What I want to do is trying run the code that in this doc from 7.1 All In User Context. In my knowing for kernel programming, I'll need to compile the code to something like `main.ko` then insert into kernel space using `insmod`. Here is the GitHub that I'm doing PoC code: https://github.com/grapherd/unreliable_guide_to_locking My question is, Is my knowing right? and, how can I use the function in main.ko (e.g. cache_add). I'm using these function by test.ko, is that a normal way to use it? in this doc have mention, there have hardirq, softirq. How can I test it from these irq method? Thanks! Louie Lu.
On 08/24/2016 01:18 PM, Louie Lu wrote:
Hi everyone,
I'm now reading *Unreliable Guide To Locking* which came from kernelnewbies.org (https://kernelnewbies.org/Documents/Kernel-Docbooks)
What I want to do is trying run the code that in this doc from 7.1 All In User Context.
In my knowing for kernel programming, I'll need to compile the code to something like `main.ko` then insert into kernel space using `insmod`.
Here is the GitHub that I'm doing PoC code: https://github.com/grapherd/unreliable_guide_to_locking
My question is, Is my knowing right? and, how can I use the function in main.ko (e.g. cache_add). I'm using these function by test.ko, is that a normal way to use it?
in this doc have mention, there have hardirq, softirq. How can I test it from these irq method?
You have to create some sort of an interface which utilizes those kernel function. That might be IOCTL or procfiles or debugfs or any other number of UM<=>KM interfaces.
Thanks! Louie Lu.
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2016-08-24 18:23 GMT+08:00 Nikolay Borisov <n.borisov.lkml@gmail.com>:
On 08/24/2016 01:18 PM, Louie Lu wrote:
Hi everyone,
I'm now reading *Unreliable Guide To Locking* which came from kernelnewbies.org (https://kernelnewbies.org/Documents/Kernel-Docbooks)
What I want to do is trying run the code that in this doc from 7.1 All In User Context.
In my knowing for kernel programming, I'll need to compile the code to something like `main.ko` then insert into kernel space using `insmod`.
Here is the GitHub that I'm doing PoC code: https://github.com/grapherd/unreliable_guide_to_locking
My question is, Is my knowing right? and, how can I use the function in main.ko (e.g. cache_add). I'm using these function by test.ko, is that a normal way to use it?
in this doc have mention, there have hardirq, softirq. How can I test it from these irq method?
You have to create some sort of an interface which utilizes those kernel function. That might be IOCTL or procfiles or debugfs or any other number of UM<=>KM interfaces.
Thanks for reply, I'm now looking for procfs example, like this: http://www.tldp.org/LDP/lkmpg/2.6/html/x710.html or this: https://kernelnewbies.org/Documents/Kernel-Docbooks?action=AttachFile&do=get... But it seems that all this tutorial were deprecate, since 3.10 change for proc_create_entry() Are there any resource for procfs to leran? thanks!. Louie Lu.
Thanks! Louie Lu.
_______________________________________________ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
You may want to look at this free course on kernel programming: http://crashcourse.ca/introduction-linux-kernel-programming/introduction- linux-kernel-programming I believe that the entire course is free now (even though it mentions costing $39). It has a section on creating proc filesystem entries. On Wed, Aug 24, 2016 at 4:39 AM, Louie Lu <louie.lu@hopebaytech.com> wrote:
2016-08-24 18:23 GMT+08:00 Nikolay Borisov <n.borisov.lkml@gmail.com>:
On 08/24/2016 01:18 PM, Louie Lu wrote:
Hi everyone,
I'm now reading *Unreliable Guide To Locking* which came from kernelnewbies.org (https://kernelnewbies.org/Documents/Kernel-Docbooks)
What I want to do is trying run the code that in this doc from 7.1 All In User Context.
In my knowing for kernel programming, I'll need to compile the code to something like `main.ko` then insert into kernel space using `insmod`.
Here is the GitHub that I'm doing PoC code: https://github.com/grapherd/unreliable_guide_to_locking
My question is, Is my knowing right? and, how can I use the function in main.ko (e.g. cache_add). I'm using these function by test.ko, is that a normal way to use it?
in this doc have mention, there have hardirq, softirq. How can I test it from these irq method?
You have to create some sort of an interface which utilizes those kernel function. That might be IOCTL or procfiles or debugfs or any other number of UM<=>KM interfaces.
Thanks for reply, I'm now looking for procfs example,
like this: http://www.tldp.org/LDP/lkmpg/2.6/html/x710.html or this: https://kernelnewbies.org/Documents/Kernel-Docbooks? action=AttachFile&do=get&target=procfs-guide_2.6.29.pdf
But it seems that all this tutorial were deprecate, since 3.10 change for proc_create_entry()
Are there any resource for procfs to leran?
thanks!.
Louie Lu.
Thanks! Louie Lu.
_______________________________________________ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
_______________________________________________ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
-- Dave Hylands Shuswap, BC, Canada http://www.davehylands.com
You may want to look at this free course on kernel programming: http://crashcourse.ca/introduction-linux-kernel-programming/introduction-lin... I believe that the entire course is free now (even though it mentions costing $39).
It has a section on creating proc filesystem entries.
Thanks for this tutorial, that's great. I'm now writing some procfs code and testing on my laptop. Is that I'll need to use VM to test the code, or just test it on my laptop? I found that if sometimes I broke my code (e.g. can't remove modules, modules panic ...etc) I need to reboot my laptop to recover from this situation. Is that how a true kernel developer does? or they will open a VM to test it, then test on real hardware PC. Thanks! 2016-08-25 7:27 GMT+08:00 Dave Hylands <dhylands@gmail.com>:
You may want to look at this free course on kernel programming: http://crashcourse.ca/introduction-linux-kernel-programming/introduction-lin... I believe that the entire course is free now (even though it mentions costing $39).
It has a section on creating proc filesystem entries.
On Wed, Aug 24, 2016 at 4:39 AM, Louie Lu <louie.lu@hopebaytech.com> wrote:
2016-08-24 18:23 GMT+08:00 Nikolay Borisov <n.borisov.lkml@gmail.com>:
On 08/24/2016 01:18 PM, Louie Lu wrote:
Hi everyone,
I'm now reading *Unreliable Guide To Locking* which came from kernelnewbies.org (https://kernelnewbies.org/Documents/Kernel-Docbooks)
What I want to do is trying run the code that in this doc from 7.1 All In User Context.
In my knowing for kernel programming, I'll need to compile the code to something like `main.ko` then insert into kernel space using `insmod`.
Here is the GitHub that I'm doing PoC code: https://github.com/grapherd/unreliable_guide_to_locking
My question is, Is my knowing right? and, how can I use the function in main.ko (e.g. cache_add). I'm using these function by test.ko, is that a normal way to use it?
in this doc have mention, there have hardirq, softirq. How can I test it from these irq method?
You have to create some sort of an interface which utilizes those kernel function. That might be IOCTL or procfiles or debugfs or any other number of UM<=>KM interfaces.
Thanks for reply, I'm now looking for procfs example,
like this: http://www.tldp.org/LDP/lkmpg/2.6/html/x710.html or this: https://kernelnewbies.org/Documents/Kernel-Docbooks?action=AttachFile&do=get...
But it seems that all this tutorial were deprecate, since 3.10 change for proc_create_entry()
Are there any resource for procfs to leran?
thanks!.
Louie Lu.
Thanks! Louie Lu.
_______________________________________________ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
_______________________________________________ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
-- Dave Hylands Shuswap, BC, Canada http://www.davehylands.com
On Thu, 25 Aug 2016 16:04:58 +0800, Louie Lu said:
Is that I'll need to use VM to test the code, or just test it on my laptop?
I found that if sometimes I broke my code (e.g. can't remove modules, modules panic ...etc) I need to reboot my laptop to recover from this situation.
Is that how a true kernel developer does? or they will open a VM to test it, then test on real hardware PC.
There's no such thing as a "true kernel developer". Some run their code in a VM because their code is something that can be tested in a VM, some test on a real hardware PC, some write the build onto a flash card and put it in a non-PC system (usually an ARM or MIPS based embedded device). All depends what your resources are, and what code you're testing.
On Wed, 24 Aug 2016 18:18:18 +0800, Louie Lu said:
in this doc have mention, there have hardirq, softirq. How can I test it from these irq method?
First, figure out if the code in question should even be called from those contexts, or if it's a bug if that happens. Hard and soft IRQ contexts are basically interrupt handlers. If your code is a "hello world" module, or if it's filesystem code, or pretty much any part of the kernel that's not a device driver, it probably should not be called from IRQ context.
participants (4)
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Dave Hylands -
Louie Lu -
Nikolay Borisov -
Valdis.Kletnieks＠vt.edu