Re: init_idle reaped before final call

["Martin J. Bligh" <Martin.Bligh@us.ibm.com>]

> I'm working with a (approximately) 2.4.17 kernel from the mips-linux
> tree (oss.sgi.com).
> 
> I'd like to propose removing the "__init" designation from init_idle in
> kernel/sched.c, since this is called from rest_init via cpu_idle. 
> Notice that rest_init isn't in an init section, and explicitly mentions
> that it's avoiding a race with free_initmem.  In my kernel (an SMP
> kernel running on a system with only 1 available CPU), cpu_idle isn't
> getting called until after free_initmem().
> 
> My CPU is MIPS, but it looks like x86 could experience the same problem.

I fixed something in this area for x86, looks like the same code path
for MIPS unless I'm misreading.

smp_init spins waiting on wait_init_idle until every cpu has done
init_idle. rest_init() isn't called until smp_init returns, so I'm not sure
how you could hit this (possibly there's a minute window after init_idle
clears the bit, but before it returns?).

M.