Re: [Bug? Report] kref problem

Greg KH
2006-03-16T17:43:04Z

On Thu, Mar 16, 2006 at 09:31:18AM -0800, Dave Hansen wrote:
> On Thu, 2006-03-16 at 08:53 -0800, Greg KH wrote:
> > On Thu, Mar 16, 2006 at 02:41:19PM +0300, Artem B. Bityutskiy wrote:
> > > struct my_obj_a
> > > {
> > > struct kobject kobj;
> > > } a;
> > >
> > > struct my_obj_b
> > > {
> > > struct kobject kobj;
> > > } b;
> >
> > Don't statically create kobjects, it's not nice. But the real problem
> > is below...
>
> This seems to be one of those top ten sysfs snafus. Could we take the
> definitions from include/asm-generic/sections.h, and make a kobject
> verification function to put in the critical generic kernel functions
> that deal with kobjects, like kobject_init()?

I wish. The main offender of this is the kernel core code itself, with
the decl_subsys and struct bus stuff. If you provide some nice fuctions
to fix those up to be dynamic, then I would have no problem with the
function you have below.

> Somthing like...
>
> void verify_dynamic_kobject_allocation(struct kobject *kobj)
> {
> if (kobj >= &_data && kobj < &_edata)
> goto warn;
> if (kobj >= &_bss_start && kobj < &_bss_end)
> goto warn;
> ...
> return;
> warn:
> printk(KERN_WARN "statically allocated kobject, you suck...\n");
> }
>
> I'm not sure that all of the architectures fill in all of the values,
> but we could at least support the warnings for the ones that do. That
> includes at least i386, so it could be a relatively effective tool.
>
> I'll cook up a real patch in a bit.

That would be fun to play with, I'd appreciate it. If nothing else,
I'll add it to my tree for future use.

thanks,

greg k-h