Rich Freeman <ri...@gentoo.org> wrote: > On Wed, Oct 7, 2015 at 4:13 PM, <cov...@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 cov...@ccs.covici.com