Re: [PATCH] kexec for 2.5.51....

From: Eric W. Biederman (
Date: Sun Dec 15 2002 - 16:03:17 EST

Ed Tomlinson <> writes:

> On December 14, 2002 02:37 pm, Eric W. Biederman wrote:
> >
> > Hurray! a bug report :)
> Feels good huh.

Getting new and interesting feedback is good. You can tell something
is happening if a bug report is submitted.

> > > One other datum. Without the --append line a kernel booted with kexec
> > > hangs when
> > >
> > > tring to mount the real root - it cannot find the device.
> >
> > I suspect you want to specify --append="root=/dev/xyz" when calling kexec.
> This helps - see below.
> > > Am I using kexec correctly? What else can I try? Is there any debug
> > > info I can gather?
> >
> > Generally you want to put kexec -e your shutdown scripts just before
> > the call to reboot. And then you can just say: kexec ...
> > and the you get a clean system shutdown. Dropping to run level 1
> Why not include this info in kexec -h ? Bet it would prevent a few
> failure reports...

I will look, at that.
> Two more possible additions to the kexec command.
> 1. kexec -q which returns rc=1 and types the pending selection and
> its command/append string if one exists and returns rc=0 if nothing
> is pending.

This would require effort to little purpose. If you just call kexec
it loads the kernel and then calls shutdown -r now. So the loaded kernel
should be a transient entity anyway.

> 2. kexec -c which clears any pending kernels.

This I can and should do. The kernel side is already implemented.
> > With respect to USB it is quite possible something in the USB drivers
> > does not shutdown correctly on a reboot, and the driver then has trouble
> > reinitializing the device.
> Very possible since I did not do an init 0/1/6 before the kexec -e. Usb
> was probably being asked to do something very unexpected...

Ideally drivers should be able to cope with this.

> > Which kernel are you booting with kexec anyway?
> 2.5.51 + fbcon(bk) + usb(bk) + kexec

Ah, the easy case kexec loading the same kernel that had the kexec support....

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This archive was generated by hypermail 2b29 : Sun Dec 15 2002 - 22:00:33 EST