[gentoo-user] kernel panick in 4.2.1 from gentoo-sources

[gentoo-user] kernel panick in 4.2.1 from gentoo-sources

[covici]

Hi.  I am getting some kind of kernel panick in 4.2.1 -- it boots up OK,
to a virtual console with a framebuffer, but after half a minute or so,
I get the kernel panick -- now nothing is preserved in the logs, so how
do I get any information about what happened -- serial console or other
means?  Can I do a console over the network without additional hardware?

The reason I went with that kernel is because I want to try btrfs and
they develop fast, so it looked from Google searching that I should be
on 4.2 or thereabouts.  The btrfs programs I emerged did say 4.2.

So, I would like to go on two paths at once -- find out about the
panick, and maybe go to a lower kernel as well, but I was concerned
about btrfs if I do that.  I have not created the pool yet.

Thanks in advance for any suggestions.

-- 
Your life is like a penny.  You're going to lose it.  The question is:
How do
you spend it?

         John Covici
         covici@ccs.covici.com

Re: [gentoo-user] kernel panick in 4.2.1 from gentoo-sources

[Rich Freeman]

On Wed, Oct 7, 2015 at 4:13 PM,  <covici@ccs.covici.com> wrote:
> Hi.  I am getting some kind of kernel panick in 4.2.1 -- it boots up OK,
> ...
> how
> do I get any information about what happened -- serial console or other
> means?  Can I do a console over the network without additional hardware?

That is pretty simple actually.

Set CONFIG_NETCONSOLE=y/m in your kernel config if it is not already set.
add to your kernel command line:
netconsole=6666@192.168.0.10/eth0,6666@192.168.0.5/1c:6f:65:ab:07:b2

(The first set of values is port@src-ip/interface.  The second set of
values is port@dest-ip/MAC.  This is low-level code in the kernel so
it is just sending raw UDP packets - the routine sending them has no
idea what your interface IP is, and it can't use ARP.)

On the destination machine, run "nc -u -l -p 6666"

That will listen for console output and dump it to stdout.  You'll get
everything that goes to dmesg on the remote machine, including
BUG/PANIC/etc output.  It works fine even if the disks stop syncing.

>
> The reason I went with that kernel is because I want to try btrfs and
> they develop fast, so it looked from Google searching that I should be
> on 4.2 or thereabouts.  The btrfs programs I emerged did say 4.2.
>

If you're having btrfs issues on such a recent kernel you should
probably at least run all the backports that are available for it.

There are undoubtedly many btrfs issues in 4.2.1 that have been fixed
in 4.2.3, so you should probably be running this version if you want
to stick with 4.2.

Personally, I've been sticking with 3.18 until 4.1 quiets down.  There
are usually regressions in any new kernel version with btrfs.

> So, I would like to go on two paths at once -- find out about the
> panick, and maybe go to a lower kernel as well, but I was concerned
> about btrfs if I do that.  I have not created the pool yet.

Generally speaking the btrfs on-disk format is stable, so for the most
part you can switch back and forth between versions without issue.  If
you want to go to a really old kernel series like maybe 3.12 there
might be a few optional btrfs features that won't work, but in general
I'd stick with something newer.

So, if you want to be bleeding-edge then stick with the bleeding edge
and run the latest stable.  If you want something longterm I'd stick
with the 1st-2nd most recent longterm.  4.1 is still pretty new, but
I'm close to switching over to it.

You'd need to post the details of the panic to know more - the btrfs
list is probably the best place.  But again I'd confirm the panic on
the latest release in the series you're running so as to not waste
time on issues that may already be fixed.

-- 
Rich

Re: [gentoo-user] kernel panick in 4.2.1 from gentoo-sources

[covici]

Rich Freeman <rich0@gentoo.org> wrote:

> On Wed, Oct 7, 2015 at 4:13 PM,  <covici@ccs.covici.com> wrote:
> > Hi.  I am getting some kind of kernel panick in 4.2.1 -- it boots up OK,
> > ...
> > how
> > do I get any information about what happened -- serial console or other
> > means?  Can I do a console over the network without additional hardware?
> 
> That is pretty simple actually.
> 
> Set CONFIG_NETCONSOLE=y/m in your kernel config if it is not already set.
> add to your kernel command line:
> netconsole=6666@192.168.0.10/eth0,6666@192.168.0.5/1c:6f:65:ab:07:b2
> 
> (The first set of values is port@src-ip/interface.  The second set of
> values is port@dest-ip/MAC.  This is low-level code in the kernel so
> it is just sending raw UDP packets - the routine sending them has no
> idea what your interface IP is, and it can't use ARP.)
> 
> On the destination machine, run "nc -u -l -p 6666"
> 
> That will listen for console output and dump it to stdout.  You'll get
> everything that goes to dmesg on the remote machine, including
> BUG/PANIC/etc output.  It works fine even if the disks stop syncing.
> 
> >
> > The reason I went with that kernel is because I want to try btrfs and
> > they develop fast, so it looked from Google searching that I should be
> > on 4.2 or thereabouts.  The btrfs programs I emerged did say 4.2.
> >
> 
> If you're having btrfs issues on such a recent kernel you should
> probably at least run all the backports that are available for it.
> 
> There are undoubtedly many btrfs issues in 4.2.1 that have been fixed
> in 4.2.3, so you should probably be running this version if you want
> to stick with 4.2.
> 
> Personally, I've been sticking with 3.18 until 4.1 quiets down.  There
> are usually regressions in any new kernel version with btrfs.
> 
> > So, I would like to go on two paths at once -- find out about the
> > panick, and maybe go to a lower kernel as well, but I was concerned
> > about btrfs if I do that.  I have not created the pool yet.
> 
> Generally speaking the btrfs on-disk format is stable, so for the most
> part you can switch back and forth between versions without issue.  If
> you want to go to a really old kernel series like maybe 3.12 there
> might be a few optional btrfs features that won't work, but in general
> I'd stick with something newer.
> 
> So, if you want to be bleeding-edge then stick with the bleeding edge
> and run the latest stable.  If you want something longterm I'd stick
> with the 1st-2nd most recent longterm.  4.1 is still pretty new, but
> I'm close to switching over to it.
> 
> You'd need to post the details of the panic to know more - the btrfs
> list is probably the best place.  But again I'd confirm the panic on
> the latest release in the series you're running so as to not waste
> time on issues that may already be fixed.


Thanks much -- 4.2.1 wqas what I just got using gentoo-sources, I will
sync and try again, maybe go to 4.1 and see what happens.  I heard 3.19
was the first version where btrfs actually worked, and I have 3.18 here,
this is why I was trying the newer kernel.  So, what is the latest lts
kernel these days anyway?

Thanks again.

-- 
Your life is like a penny.  You're going to lose it.  The question is:
How do
you spend it?

         John Covici
         covici@ccs.covici.com

Re: [gentoo-user] kernel panick in 4.2.1 from gentoo-sources

[Rich Freeman]

On Wed, Oct 7, 2015 at 7:13 PM,  <covici@ccs.covici.com> wrote:
>
> Thanks much -- 4.2.1 wqas what I just got using gentoo-sources, I will
> sync and try again, maybe go to 4.1 and see what happens.  I heard 3.19
> was the first version where btrfs actually worked, and I have 3.18 here,
> this is why I was trying the newer kernel.  So, what is the latest lts
> kernel these days anyway?
>

btrfs has been continually improved, but it has been working
reasonably well for raid0/1 or single disk since maybe the 3.12 days.

Current kernel versions are posted at https://kernel.org/

-- 
Rich

Re: [gentoo-user] kernel panick in 4.2.1 from gentoo-sources

[covici]

Rich Freeman <rich0@gentoo.org> wrote:

> On Wed, Oct 7, 2015 at 7:13 PM,  <covici@ccs.covici.com> wrote:
> >
> > Thanks much -- 4.2.1 wqas what I just got using gentoo-sources, I will
> > sync and try again, maybe go to 4.1 and see what happens.  I heard 3.19
> > was the first version where btrfs actually worked, and I have 3.18 here,
> > this is why I was trying the newer kernel.  So, what is the latest lts
> > kernel these days anyway?
> >
> 
> btrfs has been continually improved, but it has been working
> reasonably well for raid0/1 or single disk since maybe the 3.12 days.
> 
> Current kernel versions are posted at https://kernel.org/
How can I tell which ones are long term support?


-- 
Your life is like a penny.  You're going to lose it.  The question is:
How do
you spend it?

         John Covici
         covici@ccs.covici.com

Re: [gentoo-user] kernel panick in 4.2.1 from gentoo-sources

[Rich Freeman]

On Wed, Oct 7, 2015 at 8:34 PM,  <covici@ccs.covici.com> wrote:
> Rich Freeman <rich0@gentoo.org> wrote:
>
>> On Wed, Oct 7, 2015 at 7:13 PM,  <covici@ccs.covici.com> wrote:
>> >
>> > Thanks much -- 4.2.1 wqas what I just got using gentoo-sources, I will
>> > sync and try again, maybe go to 4.1 and see what happens.  I heard 3.19
>> > was the first version where btrfs actually worked, and I have 3.18 here,
>> > this is why I was trying the newer kernel.  So, what is the latest lts
>> > kernel these days anyway?
>> >
>>
>> btrfs has been continually improved, but it has been working
>> reasonably well for raid0/1 or single disk since maybe the 3.12 days.
>>
>> Current kernel versions are posted at https://kernel.org/
> How can I tell which ones are long term support?

They say longterm next to them.  :)

Stable ones will have releases for a few months typically.

Gentoo-sources keywording tends to lag a bit, though I thought they
were going to change that.  I tend to just keep my own git clone of
the kernel tree and checkout from tags.

-- 
Rich

Re: [gentoo-user] kernel panick in 4.2.1 from gentoo-sources

[covici]

Rich Freeman <rich0@gentoo.org> wrote:

> On Wed, Oct 7, 2015 at 8:34 PM,  <covici@ccs.covici.com> wrote:
> > Rich Freeman <rich0@gentoo.org> wrote:
> >
> >> On Wed, Oct 7, 2015 at 7:13 PM,  <covici@ccs.covici.com> wrote:
> >> >
> >> > Thanks much -- 4.2.1 wqas what I just got using gentoo-sources, I will
> >> > sync and try again, maybe go to 4.1 and see what happens.  I heard 3.19
> >> > was the first version where btrfs actually worked, and I have 3.18 here,
> >> > this is why I was trying the newer kernel.  So, what is the latest lts
> >> > kernel these days anyway?
> >> >
> >>
> >> btrfs has been continually improved, but it has been working
> >> reasonably well for raid0/1 or single disk since maybe the 3.12 days.
> >>
> >> Current kernel versions are posted at https://kernel.org/
> > How can I tell which ones are long term support?
> 
> They say longterm next to them.  :)
> 
> Stable ones will have releases for a few months typically.
> 
> Gentoo-sources keywording tends to lag a bit, though I thought they
> were going to change that.  I tend to just keep my own git clone of
> the kernel tree and checkout from tags.

Do you bother with the gentoo patches?

I have the kernel tree and none of the tags say longterm, do I have the
wrong tree or  something?    The url I have is
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git

-- 
Your life is like a penny.  You're going to lose it.  The question is:
How do
you spend it?

         John Covici
         covici@ccs.covici.com

Re: [gentoo-user] kernel panick in 4.2.1 from gentoo-sources

[Alec Ten Harmsel]

On Wed, Oct 07, 2015 at 10:12:28PM -0400, covici@ccs.covici.com wrote:
> Rich Freeman <rich0@gentoo.org> wrote:
> 
> > Gentoo-sources keywording tends to lag a bit, though I thought they
> > were going to change that.  I tend to just keep my own git clone of
> > the kernel tree and checkout from tags.
> 
> Do you bother with the gentoo patches?

I seem to recall the list having a discussion about gentoo-sources vs.
vanilla-sources a while ago, and I believe Rich doesn't use the gentoo
patches. It doesn't seem like he does, since just above he mentions that
he builds and runs kernels from a checkout of a git repo from
kernel.org.

> I have the kernel tree and none of the tags say longterm, do I have the
> wrong tree or  something?    The url I have is
> git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git

The stable tree is
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git.
Only X.Y tags go into Linus' git repo, not X.Y.Z. When they switched
from version 2 to version 3, the numbering scheme changed a bit. Any
kernel version with a third version number is either stable or long
term, and if the last number in the version is more than 8 or 10, it is
probably going to be a long term kernel.

This is pretty much the rationale that I use for updating - as soon as a
kernel version higher than the one I'm currently running has the last
number in the version hit 8 or 10, I upgrade.

Alec

Re: [gentoo-user] kernel panick in 4.2.1 from gentoo-sources

[covici]

Alec Ten Harmsel <alec@alectenharmsel.com> wrote:

> On Wed, Oct 07, 2015 at 10:12:28PM -0400, covici@ccs.covici.com wrote:
> > Rich Freeman <rich0@gentoo.org> wrote:
> > 
> > > Gentoo-sources keywording tends to lag a bit, though I thought they
> > > were going to change that.  I tend to just keep my own git clone of
> > > the kernel tree and checkout from tags.
> > 
> > Do you bother with the gentoo patches?
> 
> I seem to recall the list having a discussion about gentoo-sources vs.
> vanilla-sources a while ago, and I believe Rich doesn't use the gentoo
> patches. It doesn't seem like he does, since just above he mentions that
> he builds and runs kernels from a checkout of a git repo from
> kernel.org.
> 
> > I have the kernel tree and none of the tags say longterm, do I have the
> > wrong tree or  something?    The url I have is
> > git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> 
> The stable tree is
> git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git.
> Only X.Y tags go into Linus' git repo, not X.Y.Z. When they switched
> from version 2 to version 3, the numbering scheme changed a bit. Any
> kernel version with a third version number is either stable or long
> term, and if the last number in the version is more than 8 or 10, it is
> probably going to be a long term kernel.
> 
> This is pretty much the rationale that I use for updating - as soon as a
> kernel version higher than the one I'm currently running has the last
> number in the version hit 8 or 10, I upgrade.

OK, that is interesting, I like to use Linus's tree for fooling around,
so that tells me something.

-- 
Your life is like a penny.  You're going to lose it.  The question is:
How do
you spend it?

         John Covici
         covici@ccs.covici.com

Re: [gentoo-user] kernel panick in 4.2.1 from gentoo-sources

[Tuomo Hartikainen]

On 2015-10-08 07:50, Alec Ten Harmsel wrote:
> On Wed, Oct 07, 2015 at 10:12:28PM -0400, covici@ccs.covici.com wrote:
> > Rich Freeman <rich0@gentoo.org> wrote:
> > 
> > > Gentoo-sources keywording tends to lag a bit, though I thought they
> > > were going to change that.  I tend to just keep my own git clone of
> > > the kernel tree and checkout from tags.
> > 
> > Do you bother with the gentoo patches?
> 
> I seem to recall the list having a discussion about gentoo-sources vs.
> vanilla-sources a while ago, and I believe Rich doesn't use the gentoo
> patches. It doesn't seem like he does, since just above he mentions that
> he builds and runs kernels from a checkout of a git repo from
> kernel.org.
> 
> > I have the kernel tree and none of the tags say longterm, do I have the
> > wrong tree or  something?    The url I have is
> > git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> 
> The stable tree is
> git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git.
> Only X.Y tags go into Linus' git repo, not X.Y.Z. When they switched
> from version 2 to version 3, the numbering scheme changed a bit. Any
> kernel version with a third version number is either stable or long
> term, and if the last number in the version is more than 8 or 10, it is
> probably going to be a long term kernel.

They list the longterm and stable releases quite neatly on their front
page, no need for guessing: https://kernel.org/

-- 
Tuomo Hartikainen

Re: [gentoo-user] kernel panick in 4.2.1 from gentoo-sources

[Jeremi Piotrowski]

On Wed, Oct 07, 2015 at 10:12:28PM -0400, covici@ccs.covici.com wrote:
> 
> Do you bother with the gentoo patches?

Only the Kconfig patch that gives quick access to gentoo required configs
is really useful, the rest I would call minor. If you copy your config
from gentoo-sources to the git tree, the required ones will already be
active you can skip genpatches altogether.

> I have the kernel tree and none of the tags say longterm, 

The tags don't say longterm, the website (kernel.org) says which releases
are longterm support ones.

> do I have the wrong tree or  something?    The url I have is
> git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git

That's the development tree, if you want the stable/longterm releases use
this one:

    git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git

You should be able to add it to your existing tree using something like:

    git remote add stable <url>
    git fetch stable

although it does take a while ;)

Re: [gentoo-user] kernel panick in 4.2.1 from gentoo-sources

[Stefan G. Weichinger]

Am 08.10.2015 um 03:10 schrieb Rich Freeman:

> Gentoo-sources keywording tends to lag a bit, though I thought they
> were going to change that.  I tend to just keep my own git clone of
> the kernel tree and checkout from tags.

I never really understood what difference the gentoo-patches make.

gentoo-sources vs. vanilla git-clone: could you describe why to prefer
the last one?

thanks!

Re: [gentoo-user] kernel panick in 4.2.1 from gentoo-sources

[Dale]

Stefan G. Weichinger wrote:
> Am 08.10.2015 um 03:10 schrieb Rich Freeman:
>
>> Gentoo-sources keywording tends to lag a bit, though I thought they
>> were going to change that.  I tend to just keep my own git clone of
>> the kernel tree and checkout from tags.
> I never really understood what difference the gentoo-patches make.
>
> gentoo-sources vs. vanilla git-clone: could you describe why to prefer
> the last one?
>
> thanks!
>
>
>
>


Maybe this will help:

https://dev.gentoo.org/~mpagano/genpatches/about.htm

Dale

:-)  :-)