[gentoo-user] Kernel upgrading and linux symlink

[gentoo-user] Kernel upgrading and linux symlink

[Harry Putnam]

Looking at the kernel upgrade pages at 
  http://www.gentoo.org/doc/en/kernel-upgrade.xml

Its a bit confusing about the symlink creation.  I've wondered about
it a few times. 

At the top, you're told how to get the sources and then a discussion
of the symlink follows.

It appears you are expected to change the symlink to the newly
installed sources.

But then it says:
4.  Updating the /usr/src/linux symbolic link

  "Gentoo requires that the /usr/src/linux symbolic link points to the
  sources of the kernel you are running."

So if gentoo `requires' the symlink to point to the running kernel
why are we changing it to the newly installed but not yet compiled or
started kernel?

And in fact does it really matter if its pointing at the newly
installed or actual running kernel, when kernel compiling operations
take place?

[gentoo-user] Re: Kernel upgrading and linux symlink

[Nikos Chantziaras]

On 10/31/2009 06:52 PM, Harry Putnam wrote:
> Looking at the kernel upgrade pages at
>    http://www.gentoo.org/doc/en/kernel-upgrade.xml
>
> Its a bit confusing about the symlink creation.  I've wondered about
> it a few times.
>
> At the top, you're told how to get the sources and then a discussion
> of the symlink follows.
>
> It appears you are expected to change the symlink to the newly
> installed sources.
>
> But then it says:
> 4.  Updating the /usr/src/linux symbolic link
>
>    "Gentoo requires that the /usr/src/linux symbolic link points to the
>    sources of the kernel you are running."
>
> So if gentoo `requires' the symlink to point to the running kernel
> why are we changing it to the newly installed but not yet compiled or
> started kernel?
>
> And in fact does it really matter if its pointing at the newly
> installed or actual running kernel, when kernel compiling operations
> take place?

The link is created only if you have the "symlink" USE flag enabled.

Also, "Gentoo requires that the [...] symbolic link points to the 
sources of the kernel you are running" is not entirely correct.  It is 
required only when you want to build something against that kernel. 
Obviously, you need to create the symlink if you want to build the newly 
installed kernel, even though the system is still running an older one.

And, btw, the symlink is changed easily with eselect:

   eselect kernel list

to get a list and:

   eselect kernel set N

to point the symlink to the Nth kernel.

So, to sum it up, when you update to a new kernel, first update the 
symlink (or let the ebuild take care of it), build the kernel, boot it, 
*then* rebuild external modules (like ati-drivers).  If you know what 
you're doing, you don't need to reboot before rebuilding external 
modules, for example I do:

ebuild /usr/portage/x11-drivers/ati-drivers/ati-drivers-N.ebuild compile
mkdir /lib/modules/KERNEL_VERSION/video
cp 
/var/tmp/portage/x11-drivers/ati-drivers-N/work/common/lib/modules/fglrx/build_mod/2.6.x/fglrx.ko 
/lib/modules/KERNEL_VERSION/video/

But it general, just boot the new kernel and emerge external modules 
again; safer and more straight forward.

[gentoo-user] Re: Kernel upgrading and linux symlink

[Harry Putnam]

Nikos Chantziaras <realnc@arcor.de> writes:

> The link is created only if you have the "symlink" USE flag enabled.
>
> Also, "Gentoo requires that the [...] symbolic link points to the
> sources of the kernel you are running" is not entirely correct.  It is
> required only when you want to build something against that
> kernel.

> . . . .  Obviously, you need to create the symlink if you want to build
> the newly installed kernel, even though the system is still running an
> older one.

Why is that obvious?  That's what seemed confusing to me.

Nothing about creating it with USE=symlin, eselect, or by hand is a
problem. Or hard to follow, and I've always just done it by hand.

Re: [gentoo-user] Kernel upgrading and linux symlink

[Denis]

On Sat, Oct 31, 2009 at 12:52 PM, Harry Putnam <reader@newsguy.com> wrote:
> And in fact does it really matter if its pointing at the newly
> installed or actual running kernel, when kernel compiling operations
> take place?

When I upgrade a kernel, I first change the symlink using eselect to
point to the source I'm about to install.  Then, after I configure and
compile the kernel, I use the "module-rebuild rebuild" to rebuild any
kernel modules against the new source.  Move the bzImage to /boot,
reboot, and that's it.  I don't know how genkernel changes any of this
- I use manual menuconfig.

[gentoo-user] Re: Kernel upgrading and linux symlink

[Nikos Chantziaras]

On 10/31/2009 08:09 PM, Harry Putnam wrote:
> Nikos Chantziaras<realnc@arcor.de>  writes:
>
>> The link is created only if you have the "symlink" USE flag enabled.
>>
>> Also, "Gentoo requires that the [...] symbolic link points to the
>> sources of the kernel you are running" is not entirely correct.  It is
>> required only when you want to build something against that
>> kernel.
>
>> . . . .  Obviously, you need to create the symlink if you want to build
>> the newly installed kernel, even though the system is still running an
>> older one.
>
> Why is that obvious?  That's what seemed confusing to me.

How obvious it is probably depends in prior knowledge here.  There's 
absolutely nothing in a running system that needs anything from 
/usr/src/linux.  If fact, you could, completely uninstall all kernel 
sources and totally wipe out /usr/src.  It's only needed when you build 
something that needs kernel sources.

Of course if you didn't know that, then yes, it's not obvious :)

Re: [gentoo-user] Re: Kernel upgrading and linux symlink

[Alan McKinnon]

On Saturday 31 October 2009 20:09:37 Harry Putnam wrote:
> Nikos Chantziaras <realnc@arcor.de> writes:
> > The link is created only if you have the "symlink" USE flag enabled.
> >
> > Also, "Gentoo requires that the [...] symbolic link points to the
> > sources of the kernel you are running" is not entirely correct.  It is
> > required only when you want to build something against that
> > kernel.
> >
> > . . . .  Obviously, you need to create the symlink if you want to build
> > the newly installed kernel, even though the system is still running an
> > older one.
> 
> Why is that obvious?  That's what seemed confusing to me.
> 
> Nothing about creating it with USE=symlin, eselect, or by hand is a
> problem. Or hard to follow, and I've always just done it by hand.
> 

Nikos is being kind to the document writers :-)

In fact, the documentation is flat out wrong - there is no requirement for the 
symlink to point to the currently running kernel. It must point to the kernel 
sources you want to *configure* or use for an emerge that installs a kernel 
driver.

For instance, you might be running 2.6.31-r4 and also have 2.6.31-r3 
installed. To install nvidia-drivers, you must build it *twice* - against each 
kernel you want to use it with (nvidia-drivers builds and installs a kernel 
driver into /lib/modules/<kernel version>)

USE="symlink" just runs 
ln -sfn /usr/src/<new_version> linux
at the end of the merge , no further magic. It's purely a convenience thing, 
you can just as easily do that step yourself


-- 
alan dot mckinnon at gmail dot com

[gentoo-user] Re: Kernel upgrading and linux symlink

[Nikos Chantziaras]

On 10/31/2009 09:18 PM, Alan McKinnon wrote:
> On Saturday 31 October 2009 20:09:37 Harry Putnam wrote:
>> Nikos Chantziaras<realnc@arcor.de>  writes:
>>> The link is created only if you have the "symlink" USE flag enabled.
>>>
>>> Also, "Gentoo requires that the [...] symbolic link points to the
>>> sources of the kernel you are running" is not entirely correct.  It is
>>> required only when you want to build something against that
>>> kernel.
>>>
>>> . . . .  Obviously, you need to create the symlink if you want to build
>>> the newly installed kernel, even though the system is still running an
>>> older one.
>>
>> Why is that obvious?  That's what seemed confusing to me.
>>
>> Nothing about creating it with USE=symlin, eselect, or by hand is a
>> problem. Or hard to follow, and I've always just done it by hand.
>>
>
> Nikos is being kind to the document writers :-)
>
> In fact, the documentation is flat out wrong - there is no requirement for the
> symlink to point to the currently running kernel. It must point to the kernel
> sources you want to *configure* or use for an emerge that installs a kernel
> driver.
>
> For instance, you might be running 2.6.31-r4 and also have 2.6.31-r3
> installed. To install nvidia-drivers, you must build it *twice* - against each
> kernel you want to use it with (nvidia-drivers builds and installs a kernel
> driver into /lib/modules/<kernel version>)

It's a bit more obfuscated than that.  Maybe nvidia-drivers work 
different, but ati-drivers will build against /usr/src/linux but install 
the actual modules in /lib/modules/running_kernel.  If /usr/src/linux 
doesn't point to the running kernel, the modules will be installed in 
the wrong place.

[gentoo-user] Re: Kernel upgrading and linux symlink

[Harry Putnam]

Alan McKinnon <alan.mckinnon@gmail.com> writes:

> Nikos is being kind to the document writers :-)

Thanks for saving me from the Dunce cap...hehe.

But I might yet acquire full rights to it..

So, is the symlink not really necessary?  Doe something look at
/usr/src/linux for files?

For example, if you cd 'ed into the sources top dir.  And started
`make' (after the makeconfig step), would it matter if there was a
symlink or not?

(In the instant case I did create the symlink looking at newest
sources, so all is well I hope... have yet to boot the creation.
Waiting on some emerging left in emerge -vuD system)

Re: [gentoo-user] Re: Kernel upgrading and linux symlink

[Neil Bothwick]

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On Sat, 31 Oct 2009 20:00:35 +0200, Nikos Chantziaras wrote:

> So, to sum it up, when you update to a new kernel, first update the 
> symlink (or let the ebuild take care of it), build the kernel, boot it, 
> *then* rebuild external modules (like ati-drivers).  If you know what 
> you're doing, you don't need to reboot before rebuilding external 
> modules, for example I do:
> 
> ebuild /usr/portage/x11-drivers/ati-drivers/ati-drivers-N.ebuild compile
> mkdir /lib/modules/KERNEL_VERSION/video
> cp 
> /var/tmp/portage/x11-drivers/ati-drivers-N/work/common/lib/modules/fglrx/build_mod/2.6.x/fglrx.ko 
> /lib/modules/KERNEL_VERSION/video/

I don't use ati, but with other modules, this is not necessary. As long
as /usr/srx/linux contains a valid .config, you can build modules against
that kernel without running or even compiling it.


-- 
Neil Bothwick

Thesaurus: ancient reptile with an excellent vocabulary

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Re: [gentoo-user] Re: Kernel upgrading and linux symlink

[Alan McKinnon]

On Saturday 31 October 2009 22:06:35 Harry Putnam wrote:
> Alan McKinnon <alan.mckinnon@gmail.com> writes:
> > Nikos is being kind to the document writers :-)
> 
> Thanks for saving me from the Dunce cap...hehe.
> 
> But I might yet acquire full rights to it..
> 
> So, is the symlink not really necessary?  Doe something look at
> /usr/src/linux for files?

Yes, almost every app that installs kernel drivers will go to /usr/src/linux/ 
looking for kernel sources

> For example, if you cd 'ed into the sources top dir.  And started
> `make' (after the makeconfig step), would it matter if there was a
> symlink or not?

It doesn't matter at all. There's a Makefile in that directory and it will do 
whatever it's supposed to do. The symlink to it is irrelevant and is only 
there as a shortcut with a known name


-- 
alan dot mckinnon at gmail dot com

Re: [gentoo-user] Re: Kernel upgrading and linux symlink

[Alan McKinnon]

On Saturday 31 October 2009 22:03:04 Nikos Chantziaras wrote:
> > For instance, you might be running 2.6.31-r4 and also have 2.6.31-r3
> > installed. To install nvidia-drivers, you must build it twice - against
> > each kernel you want to use it with (nvidia-drivers builds and installs a
> > kernel driver into /lib/modules/<kernel version>)
> 
> It's a bit more obfuscated than that.  Maybe nvidia-drivers work 
> different, but ati-drivers will build against /usr/src/linux but install 
> the actual modules in /lib/modules/running_kernel.  If /usr/src/linux 
> doesn't point to the running kernel, the modules will be installed in 
> the wrong place.


That is just so mind-bogglingly absurdly stupid I doubt if ATI should even be 
allowed near a computer....

Compiling code never depends on something running, it only depends on things 
being present that can be linked against.

Thanks for reminding me why I insist on NVidia GPUs, I'd forgotten.

-- 
alan dot mckinnon at gmail dot com

Re: [gentoo-user] Kernel upgrading and linux symlink

[Dale]

Denis wrote:
> On Sat, Oct 31, 2009 at 12:52 PM, Harry Putnam <reader@newsguy.com> wrote:
>   
>> And in fact does it really matter if its pointing at the newly
>> installed or actual running kernel, when kernel compiling operations
>> take place?
>>     
>
> When I upgrade a kernel, I first change the symlink using eselect to
> point to the source I'm about to install.  Then, after I configure and
> compile the kernel, I use the "module-rebuild rebuild" to rebuild any
> kernel modules against the new source.  Move the bzImage to /boot,
> reboot, and that's it.  I don't know how genkernel changes any of this
> - I use manual menuconfig.
>
>
>   

I'm about the same.  I update the symlink, build the kernel, update
nvidia-drivers against the new kernel before I forget, copy bzImage to
/boot and edit grub.  I reboot when I get the chance.

If the kernel is borked, I change the symlink back and reboot to my old
kernel.  I try to keep the symlink pointing to the kernel I am running
even if it is not absolutely necessary.

Dale

:-)  :-) 

[gentoo-user] Re: Kernel upgrading and linux symlink

[Nikos Chantziaras]

On 10/31/2009 11:07 PM, Alan McKinnon wrote:
> On Saturday 31 October 2009 22:03:04 Nikos Chantziaras wrote:
>>> For instance, you might be running 2.6.31-r4 and also have 2.6.31-r3
>>> installed. To install nvidia-drivers, you must build it twice - against
>>> each kernel you want to use it with (nvidia-drivers builds and installs a
>>> kernel driver into /lib/modules/<kernel version>)
>>
>> It's a bit more obfuscated than that.  Maybe nvidia-drivers work
>> different, but ati-drivers will build against /usr/src/linux but install
>> the actual modules in /lib/modules/running_kernel.  If /usr/src/linux
>> doesn't point to the running kernel, the modules will be installed in
>> the wrong place.
>
>
> That is just so mind-bogglingly absurdly stupid I doubt if ATI should even be
> allowed near a computer....
>
> Compiling code never depends on something running, it only depends on things
> being present that can be linked against.
>
> Thanks for reminding me why I insist on NVidia GPUs, I'd forgotten.

This isn't ATI's installer.  It's the ebuild that does this.

Re: [gentoo-user] Re: Kernel upgrading and linux symlink

[Mark Knecht]

On Sat, Oct 31, 2009 at 2:27 PM, Nikos Chantziaras <realnc@arcor.de> wrote:
> On 10/31/2009 11:07 PM, Alan McKinnon wrote:
>>
>> On Saturday 31 October 2009 22:03:04 Nikos Chantziaras wrote:
>>>>
>>>> For instance, you might be running 2.6.31-r4 and also have 2.6.31-r3
>>>> installed. To install nvidia-drivers, you must build it twice - against
>>>> each kernel you want to use it with (nvidia-drivers builds and installs
>>>> a
>>>> kernel driver into /lib/modules/<kernel version>)
>>>
>>> It's a bit more obfuscated than that.  Maybe nvidia-drivers work
>>> different, but ati-drivers will build against /usr/src/linux but install
>>> the actual modules in /lib/modules/running_kernel.  If /usr/src/linux
>>> doesn't point to the running kernel, the modules will be installed in
>>> the wrong place.
>>
>>
>> That is just so mind-bogglingly absurdly stupid I doubt if ATI should even
>> be
>> allowed near a computer....
>>
>> Compiling code never depends on something running, it only depends on
>> things
>> being present that can be linked against.
>>
>> Thanks for reminding me why I insist on NVidia GPUs, I'd forgotten.
>
> This isn't ATI's installer.  It's the ebuild that does this.

And from deep memory it seems like there were other packages that
operated this way 8-10 years ago. I know in 1999 I had to be very
careful about where the linux link pointed, and while it's not as
necessary today to do so i'm still quite careful.

I use the ATI drivers on my AMD64 machine. I think I've always found
that I needed to emerge fglrx after the new kernel had been booted but
never understood why. This email is helpful. It seems to me that if it
is the ebuild that's doing this is needs to be fixed. If I understand
correctly I could be building for 2.6.31 but installing in 2.6.29?
That's not right...

Thanks to all for the info.

Cheers,
Mark

Re: [gentoo-user] Re: Kernel upgrading and linux symlink

[Alan McKinnon]

On Saturday 31 October 2009 23:43:21 Mark Knecht wrote:
> On Sat, Oct 31, 2009 at 2:27 PM, Nikos Chantziaras <realnc@arcor.de> wrote:
> > On 10/31/2009 11:07 PM, Alan McKinnon wrote:
> >> On Saturday 31 October 2009 22:03:04 Nikos Chantziaras wrote:
> >>>> For instance, you might be running 2.6.31-r4 and also have 2.6.31-r3
> >>>> installed. To install nvidia-drivers, you must build it twice -
> >>>> against each kernel you want to use it with (nvidia-drivers builds and
> >>>> installs a
> >>>> kernel driver into /lib/modules/<kernel version>)
> >>>
> >>> It's a bit more obfuscated than that.  Maybe nvidia-drivers work
> >>> different, but ati-drivers will build against /usr/src/linux but
> >>> install the actual modules in /lib/modules/running_kernel.  If
> >>> /usr/src/linux doesn't point to the running kernel, the modules will be
> >>> installed in the wrong place.
> >>
> >> That is just so mind-bogglingly absurdly stupid I doubt if ATI should
> >> even be
> >> allowed near a computer....
> >>
> >> Compiling code never depends on something running, it only depends on
> >> things
> >> being present that can be linked against.
> >>
> >> Thanks for reminding me why I insist on NVidia GPUs, I'd forgotten.
> >
> > This isn't ATI's installer.  It's the ebuild that does this.
> 
> And from deep memory it seems like there were other packages that
> operated this way 8-10 years ago. I know in 1999 I had to be very
> careful about where the linux link pointed, and while it's not as
> necessary today to do so i'm still quite careful.
> 
> I use the ATI drivers on my AMD64 machine. I think I've always found
> that I needed to emerge fglrx after the new kernel had been booted but
> never understood why. This email is helpful. It seems to me that if it
> is the ebuild that's doing this is needs to be fixed. If I understand
> correctly I could be building for 2.6.31 but installing in 2.6.29?
> That's not right...

I agree, the ebuild should be fixed. I can't think of any valid reason for 
that behaviour.

-- 
alan dot mckinnon at gmail dot com

Re: [gentoo-user] Kernel upgrading and linux symlink

[Alan McKinnon]

On Saturday 31 October 2009 23:26:33 Dale wrote:
> Denis wrote:
> > On Sat, Oct 31, 2009 at 12:52 PM, Harry Putnam <reader@newsguy.com> wrote:
> >> And in fact does it really matter if its pointing at the newly
> >> installed or actual running kernel, when kernel compiling operations
> >> take place?
> >
> > When I upgrade a kernel, I first change the symlink using eselect to
> > point to the source I'm about to install.  Then, after I configure and
> > compile the kernel, I use the "module-rebuild rebuild" to rebuild any
> > kernel modules against the new source.  Move the bzImage to /boot,
> > reboot, and that's it.  I don't know how genkernel changes any of this
> > - I use manual menuconfig.
> 
> I'm about the same.  I update the symlink, build the kernel, update
> nvidia-drivers against the new kernel before I forget, copy bzImage to
> /boot and edit grub.  I reboot when I get the chance.

I'm a forgetful old git. In my world it usually goes like this:

emerge, build, install new kernel
carry on with work
boot into new kernel at some later point
observe xdm doing nothing on-screen
curse and swear mightily
Ctrl-Alt-F1
login as root
check symlink
module-rebuild rebuild
modprobe -r nvidia && modprobe nvidia
/etc/init.d/xdm restart && logout

takes about 6 minutes total, 6 minutes that I'll never get back :-)

-- 
alan dot mckinnon at gmail dot com

Re: [gentoo-user] Kernel upgrading and linux symlink

[Dale]

Alan McKinnon wrote:
> On Saturday 31 October 2009 23:26:33 Dale wrote:
>   
>> Denis wrote:
>>     
>>> On Sat, Oct 31, 2009 at 12:52 PM, Harry Putnam <reader@newsguy.com> wrote:
>>>       
>>>> And in fact does it really matter if its pointing at the newly
>>>> installed or actual running kernel, when kernel compiling operations
>>>> take place?
>>>>         
>>> When I upgrade a kernel, I first change the symlink using eselect to
>>> point to the source I'm about to install.  Then, after I configure and
>>> compile the kernel, I use the "module-rebuild rebuild" to rebuild any
>>> kernel modules against the new source.  Move the bzImage to /boot,
>>> reboot, and that's it.  I don't know how genkernel changes any of this
>>> - I use manual menuconfig.
>>>       
>> I'm about the same.  I update the symlink, build the kernel, update
>> nvidia-drivers against the new kernel before I forget, copy bzImage to
>> /boot and edit grub.  I reboot when I get the chance.
>>     
>
> I'm a forgetful old git. In my world it usually goes like this:
>
> emerge, build, install new kernel
> carry on with work
> boot into new kernel at some later point
> observe xdm doing nothing on-screen
> curse and swear mightily
> Ctrl-Alt-F1
> login as root
> check symlink
> module-rebuild rebuild
> modprobe -r nvidia && modprobe nvidia
> /etc/init.d/xdm restart && logout
>
> takes about 6 minutes total, 6 minutes that I'll never get back :-)
>
>   

Well, I'm a bit of a old git too.  I just sort of build habits when I am
doing something which helps me to not forget.  I'm dreading the new
baselayout upgrade.  I don't have a "habit" for that yet.  lol 

Dale

:-)  :-) 

Re: [gentoo-user] Kernel upgrading and linux symlink

[Alan McKinnon]

On Sunday 01 November 2009 00:52:42 Dale wrote:
> > emerge, build, install new kernel
> > carry on with work
> > boot into new kernel at some later point
> > observe xdm doing nothing on-screen
> > curse and swear mightily
> > Ctrl-Alt-F1
> > login as root
> > check symlink
> > module-rebuild rebuild
> > modprobe -r nvidia && modprobe nvidia
> > /etc/init.d/xdm restart && logout
> >
> > takes about 6 minutes total, 6 minutes that I'll never get back :-)
> >
> >   
> 
> Well, I'm a bit of a old git too.  I just sort of build habits when I am
> doing something which helps me to not forget.  I'm dreading the new
> baselayout upgrade.  I don't have a "habit" for that yet.  lol 

Go on, do it. You know you want to :-)

Besides, what else do you have to do with your time except read new stuff in 
/etc/conf.d/ ?

-- 
alan dot mckinnon at gmail dot com

Re: [gentoo-user] Kernel upgrading and linux symlink

[Neil Bothwick]

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On Sun, 1 Nov 2009 00:20:57 +0200, Alan McKinnon wrote:

> I'm a forgetful old git. In my world it usually goes like this:
> 
> emerge, build, install new kernel
> carry on with work
> boot into new kernel at some later point
> observe xdm doing nothing on-screen
> curse and swear mightily
> Ctrl-Alt-F1
> login as root
> check symlink
> module-rebuild rebuild
> modprobe -r nvidia && modprobe nvidia
> /etc/init.d/xdm restart && logout
> 
> takes about 6 minutes total, 6 minutes that I'll never get back :-)

That's why I use a script to build and install the kernel and then
install any external modules. With video drivers it's merely an
inconvenience if you forget, but with wireless drivers, especially
with DISTDIR on NFS, it means I would have to reboot back to the old
kernel again.


-- 
Neil Bothwick

If you think that there is good in everybody, you haven't met everybody.

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Re: [gentoo-user] Kernel upgrading and linux symlink

[Mark Knecht]

On Sat, Oct 31, 2009 at 3:20 PM, Alan McKinnon <alan.mckinnon@gmail.com> wrote:
> On Saturday 31 October 2009 23:26:33 Dale wrote:
>> Denis wrote:
>> > On Sat, Oct 31, 2009 at 12:52 PM, Harry Putnam <reader@newsguy.com> wrote:
>> >> And in fact does it really matter if its pointing at the newly
>> >> installed or actual running kernel, when kernel compiling operations
>> >> take place?
>> >
>> > When I upgrade a kernel, I first change the symlink using eselect to
>> > point to the source I'm about to install.  Then, after I configure and
>> > compile the kernel, I use the "module-rebuild rebuild" to rebuild any
>> > kernel modules against the new source.  Move the bzImage to /boot,
>> > reboot, and that's it.  I don't know how genkernel changes any of this
>> > - I use manual menuconfig.
>>
>> I'm about the same.  I update the symlink, build the kernel, update
>> nvidia-drivers against the new kernel before I forget, copy bzImage to
>> /boot and edit grub.  I reboot when I get the chance.
>
> I'm a forgetful old git. In my world it usually goes like this:
>
> emerge, build, install new kernel
> carry on with work
> boot into new kernel at some later point
> observe xdm doing nothing on-screen
> curse and swear mightily
> Ctrl-Alt-F1
> login as root
> check symlink
> module-rebuild rebuild
> modprobe -r nvidia && modprobe nvidia
> /etc/init.d/xdm restart && logout
>
> takes about 6 minutes total, 6 minutes that I'll never get back :-)
>
> --
> alan dot mckinnon at gmail dot com

So I think this thread addresses a question I've had about the kernel
installation process over the years. I only copy bzImage to /boot with
a rename to whatever this kernel is. I don't do anything with the
other files - System.map and something else - which I don't even have
on most of my systems anymore. They don't seem to be needed. Are they
just things used in the old days but now too outdated or replaced by
other stuff? (Like config.gz in the kernel, etc.)

Thanks,
Mark

[gentoo-user] Re: Kernel upgrading and linux symlink

[walt]

On 10/31/2009 04:29 PM, Mark Knecht wrote:

> So I think this thread addresses a question I've had about the kernel
> installation process over the years. I only copy bzImage to /boot with
> a rename to whatever this kernel is. I don't do anything with the
> other files - System.map and something else - which I don't even have
> on most of my systems anymore. They don't seem to be needed...

They're needed if you are trying to debug kernel crashes, but AFAIK
not needed for anything else.

Re: [gentoo-user] Kernel upgrading and linux symlink

[Alan McKinnon]

On Sunday 01 November 2009 01:29:27 Mark Knecht wrote:
> So I think this thread addresses a question I've had about the kernel
> installation process over the years. I only copy bzImage to /boot with
> a rename to whatever this kernel is. I don't do anything with the
> other files - System.map and something else - which I don't even have
> on most of my systems anymore. They don't seem to be needed. Are they
> just things used in the old days but now too outdated or replaced by
> other stuff? (Like config.gz in the kernel, etc.)
> 

just run 

make && make modules_install && make install

and everything gets moved to /boot and renamed. Don't worry about extra files, 
they're small and not worthy of concern


-- 
alan dot mckinnon at gmail dot com

Re: [gentoo-user] Re: Kernel upgrading and linux symlink

[Mark Knecht]

On Sat, Oct 31, 2009 at 4:40 PM, walt <w41ter@gmail.com> wrote:
> On 10/31/2009 04:29 PM, Mark Knecht wrote:
>
>> So I think this thread addresses a question I've had about the kernel
>> installation process over the years. I only copy bzImage to /boot with
>> a rename to whatever this kernel is. I don't do anything with the
>> other files - System.map and something else - which I don't even have
>> on most of my systems anymore. They don't seem to be needed...
>
> They're needed if you are trying to debug kernel crashes, but AFAIK
> not needed for anything else.
>

Thanks.

- Mark

Re: [gentoo-user] Kernel upgrading and linux symlink

[Mike Edenfield]

On 10/31/2009 7:29 PM, Mark Knecht wrote:

> So I think this thread addresses a question I've had about the kernel
> installation process over the years. I only copy bzImage to /boot with
> a rename to whatever this kernel is. I don't do anything with the
> other files - System.map and something else - which I don't even have
> on most of my systems anymore. They don't seem to be needed. Are they
> just things used in the old days but now too outdated or replaced by
> other stuff? (Like config.gz in the kernel, etc.)

Having a copy of the config file is useful, for me anyway, 
when I have multiple types of kernel (one without PaX, one 
without SELinux, whatever) and a new version comes out, I 
can copy its config from /boot to .config and run make 
oldconfig.

The System.map file is probably the least useful of the 
three for the average user.  It's main use is for address 
resolution in oops messages.  I think ps uses it for 
something as well.

--Mike

Re: [gentoo-user] Kernel upgrading and linux symlink

[Mark Knecht]

On Sat, Oct 31, 2009 at 4:41 PM, Alan McKinnon <alan.mckinnon@gmail.com> wrote:
> On Sunday 01 November 2009 01:29:27 Mark Knecht wrote:
>> So I think this thread addresses a question I've had about the kernel
>> installation process over the years. I only copy bzImage to /boot with
>> a rename to whatever this kernel is. I don't do anything with the
>> other files - System.map and something else - which I don't even have
>> on most of my systems anymore. They don't seem to be needed. Are they
>> just things used in the old days but now too outdated or replaced by
>> other stuff? (Like config.gz in the kernel, etc.)
>>
>
> just run
>
> make && make modules_install && make install
>
> and everything gets moved to /boot and renamed. Don't worry about extra files,
> they're small and not worthy of concern
>
>
> --
> alan dot mckinnon at gmail dot com
>
>
I don't run make install as it requires (or used to anyway) /boot to
be mounted which mine never is unless I'm copying the kernel over.
That's why I do the copy by hand.

I could put it all in a script like Neil and others seem to do but
I'll forget the script is there and not use it. I've done that before!

Thanks,
Mark

Re: [gentoo-user] Kernel upgrading and linux symlink

[Dirk Heinrichs]

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Am Samstag 31 Oktober 2009 17:52:52 schrieb Harry Putnam:
> And in fact does it really matter if its pointing at the newly
> installed or actual running kernel, when kernel compiling operations
> take place?

No, it doesn't really matter at all. AFAIK, kernel devs even recommend against 
the symlink. And you can do just fine w/o it.

I need to compile one external module, nvidia. This can be done by providing 
some ENV variables which point to the correct kernel source:

KBUILD_OUTPUT=/lib/modules/`uname -r`/build KERNEL_DIR=/lib/modules/`uname -
r`/source paludis -i1 nvidia-drivers

This points to the currently running kernel. You can easily replace "`uname -
r`" with any version you want.

Why do I do this? Because I always use the sources from kernel.org directly, 
and get them via git. I have cloned the kernel tree in /usr/src/linux-2.6, so 
that I can easily switch between different version by means of a simple "git 
checkout". The build output is stored in /usr/src/build-<version>, by using 
"make O=../build-2.6.31 menuconfig", for example.

HTH...

	Dirk

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Re: [gentoo-user] Re: Kernel upgrading and linux symlink

[Dirk Heinrichs]

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Am Samstag 31 Oktober 2009 22:03:03 schrieb Alan McKinnon:
> Yes, almost every app that installs kernel drivers will go to
>  /usr/src/linux/  looking for kernel sources

Nope. They look into $KBUILD_OUTPUT and $KERNEL_DIR, which both default to 
/usr/src/linux.

Bye...

	Dirk

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