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

[Eric W. Biederman]

Ed Tomlinson <[e-mail]> 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....

Eric