kexec+kdump + vmcoreinfo patch

[Randy Dunlap]

On Mon, 27 Aug 2007 12:55:38 -0400 Neil Horman wrote:

> On Sun, Aug 26, 2007 at 10:04:31AM -0700, Randy Dunlap wrote:
> > On Sun, 26 Aug 2007 09:23:05 -0400 Neil Horman wrote:
> > 
> > > On Fri, Aug 24, 2007 at 05:01:39PM -0700, Randy Dunlap wrote:
> > > > On Fri, 24 Aug 2007 14:41:47 -0700 Randy Dunlap wrote:
> > > > 
> > > > > Hi,
> > > > > 
> > > > > I'm trying to use the recent vmcoreinfo patch...
> > > > 
> > > > > c.  My 2.6.23-rc3 dump-capture kernel currently faults a few times,
> > > > > then it panics.  I'll add a serial console and capture its output
> > > > > to see what is going on.
> > > > 
> > > > I booted 3 times with no problems (without serial console on the
> > > > dump-capture kernel), then I added a serial console to that kernel
> > > > and got lots of problems.  They all seem to be OOM problems, then
> > > > the kernel gives up and falls over.  (log attached)
> > > > 
> > > haven't looked at your log yet, but how much memory are you passing in your
> > > crashkernel parameter in your first kernel boot?  Nominally 64MB is the minimum
> > > recommended for most kernel configurations
> > 
> > Hi Neil,
> > 
> > crashkernel=64M at 16M
> > 
> Hmm, well that should be enough.  looking at your log, it appears as though you
> have a 512k chunk allocatable, which should seem sufficient to go on a little
> longer.  The fact that your not seems to indicate that you are allocating a
> suspiciously large single chunk of ram.  I'd configure your initramfs to drop to
> a shell prompt before it sets up lp0.  Then you can step through the actions of
> the init script and monitor the contents of /proc/slabinfo to get an idea of
> whats eating up all your lowmem prior to the oom kill.

I don't have an initramfs (nor an initrd).
Is one required for using kexec + kdump?

Anyway, I'll try to do your suggestion somehow.  Thanks.

> > > > d.  Documentation/kdump/kdump.txt mentions an option to produce
> > > > ELF32 headers instead of 64-bit headers:  --elf32-core-headers.
> > > > Where is this option used?  I.e., what program recognizes it?
> > > > kdump.txt isn't telling me this info and I can't read it between
> > > > the lines.


---
~Randy
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