[lkcd-devel] Re: [Fastboot] Re: Kexec on 2.5.59 problems ?

[Suparna B. <su...@in...>]

On Mon, Feb 10, 2003 at 11:07:06AM -0700, Eric W. Biederman wrote:
> Andy Pfiffer <an...@os...> writes:
> 
> > On Mon, 2003-02-10 at 03:14, Suparna Bhattacharya wrote:
> > > Surprisingly though, when I tried just a simple 
> > > kexec -e today (having loaded the kernel earlier on), 
> > > I ran into the following Oops, consistently:
> > > 
> > > I'm using kexec-tools-1.8, and this has worked for me
> > > earlier. The test system is a 4way SMP machine.
> > > 
> > > Has anyone seen this as well ?  (I'd already issued init 1 
> > > and unmounted filesystems by this point)
> 
> Hmm.  Would love to know which cpu this is on...
> 
> I think the primary candidate if this only occurs in smp is
> the switch_mm.  It may be that modifying the init_mm is not safe,
> or it gets zapped somewhere else.
> 

The following patch from Anton Blanchard's WIP kexec tree 
for ppc64 seems to fix this for me. It just does a use_mm() 
(routine from fs/aio.c) instead of switch_mm(). 

Andy could you try this out and see if it helps  ?

The other change in Anton's tree that we should probably
include uses a separate kexec_mm rather than init_mm
for the mapping. 

Regards
Suparna

-- 
Suparna Bhattacharya (su...@in...)
Linux Technology Center
IBM Software Labs, India