Tips for a Newcomer

Tips for a Newcomer

[Logan Blyth]

Hello list,

I am looking for some tips on starting as a kernel janitor, and I was 
hoping to find out the general work flow that people use. From what I 
can tell, we search through the kernel-next git repo, then either by 
grep, ctags, or some other method? We are looking for things in the 
KernelJanitors/Todo, possibly stuff turned up by sparse? Maybe a 
different static analyser like from clang?

 From there we make sure the patch applys cleanly and mail the 
maintainer, copying the LKML and Kernel-Janitors?

Are there any recommended tutorials / Articles that google doesn't turn up?

Re: Tips for a Newcomer

[Dan Carpenter]

On Sun, Jun 30, 2013 at 05:19:19PM -0400, Logan Blyth wrote:
> Hello list,
> 
> I am looking for some tips on starting as a kernel janitor, and I
> was hoping to find out the general work flow that people use. From
> what I can tell, we search through the kernel-next git repo, then
> either by grep, ctags, or some other method?

I use cscope with vim.  There is a "make cscope" build target.

> We are looking for
> things in the KernelJanitors/Todo, possibly stuff turned up by
> sparse? Maybe a different static analyser like from clang?

Yeah.  That's a lot of it.  I don't think anyone is doing clang so
you could find some unique bugs that way.  Do you know how to get
clang working for the kernel?

> 
> From there we make sure the patch applys cleanly and mail the
> maintainer, copying the LKML and Kernel-Janitors?

Yep.  Use scripts/get_maintainer.pl.  Send your first patch to
kernel janitors without CC'd the maintainer so we can check it for
you.

regards,
dan carpenter

Re: Tips for a Newcomer

[Logan Blyth]

On 07/03/2013 03:28 AM, Dan Carpenter wrote:
> On Sun, Jun 30, 2013 at 05:19:19PM -0400, Logan Blyth wrote:
>> Hello list,
>>
>> I am looking for some tips on starting as a kernel janitor, and I
>> was hoping to find out the general work flow that people use. From
>> what I can tell, we search through the kernel-next git repo, then
>> either by grep, ctags, or some other method?
> I use cscope with vim.  There is a "make cscope" build target.
>
>> We are looking for
>> things in the KernelJanitors/Todo, possibly stuff turned up by
>> sparse? Maybe a different static analyser like from clang?
> Yeah.  That's a lot of it.  I don't think anyone is doing clang so
> you could find some unique bugs that way.  Do you know how to get
> clang working for the kernel?
I thought I did, turns out, I am struggling. I am planning on watching 
this video
http://video.linux.com/videos/applying-clang-static-analyzer-to-linux-kernel
but it is 30 min, and I am about to head off to work. I am also having 
some problems finding bugs, I saw that we should be looking in 
drivers/staging for bugs, Do we need to make changes to the .config to 
get those to show up in the tools (clang, smatch, sparse)? If so, are 
their any other changes?

I would like to compile all the info and tips I have been seeing into a 
web page. If anyone wants to add to the info, I am happy to hear advice.
>>  From there we make sure the patch applys cleanly and mail the
>> maintainer, copying the LKML and Kernel-Janitors?
> Yep.  Use scripts/get_maintainer.pl.  Send your first patch to
> kernel janitors without CC'd the maintainer so we can check it for
> you.
>
> regards,
> dan carpenter
>

Re: Tips for a Newcomer

[Darryl L. Pierce]

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On Thu, Jul 25, 2013 at 08:13:36AM -0400, Logan Blyth wrote:
> I would like to compile all the info and tips I have been seeing
> into a web page. If anyone wants to add to the info, I am happy to
> hear advice.

I'd be interested in that. I've been lurking for a while, playing with
the kernel code as time permits, but would like to dive more deeply into
it and start contributing.

-- 
Darryl L. Pierce <mcpierce@gmail.com>
http://mcpierce.fedorapeople.org/
"What do you care what people think, Mr. Feynman?"

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Re: Tips for a Newcomer

[Dan Carpenter]

On Thu, Jul 25, 2013 at 08:13:36AM -0400, Logan Blyth wrote:
> 
> On 07/03/2013 03:28 AM, Dan Carpenter wrote:
> >On Sun, Jun 30, 2013 at 05:19:19PM -0400, Logan Blyth wrote:
> >>Hello list,
> >>
> >>I am looking for some tips on starting as a kernel janitor, and I
> >>was hoping to find out the general work flow that people use. From
> >>what I can tell, we search through the kernel-next git repo, then
> >>either by grep, ctags, or some other method?
> >I use cscope with vim.  There is a "make cscope" build target.
> >
> >>We are looking for
> >>things in the KernelJanitors/Todo, possibly stuff turned up by
> >>sparse? Maybe a different static analyser like from clang?
> >Yeah.  That's a lot of it.  I don't think anyone is doing clang so
> >you could find some unique bugs that way.  Do you know how to get
> >clang working for the kernel?
> I thought I did, turns out, I am struggling. I am planning on
> watching this video
> http://video.linux.com/videos/applying-clang-static-analyzer-to-linux-kernel
> but it is 30 min, and I am about to head off to work. I am also
> having some problems finding bugs, I saw that we should be looking
> in drivers/staging for bugs, Do we need to make changes to the
> .config to get those to show up in the tools (clang, smatch,
> sparse)? If so, are their any other changes?
> 

Watch the video on clang.  It's pretty complicated from what I
remember, but maybe it's easier these days.

Someone already posted the links for sparse.

For Smatch the commands are:

git clone git://repo.or.cz/smatch.git
cd smatch
make
cd ~/kernel/src/

From here you could build the database (optional):
~/progs/smatch/devel/smatch_scripts/build_kernel_data.sh

To test the whole kernel the command is:
~/progs/smatch/devel/smatch_scripts/test_kernel.sh
creates a warns.txt file at the end.

Or to test only one file the command is:
~/progs/smatch/devel/smatch_scripts/kchecker drivers/file.c

regards,
dan carpenter