Re: [patch 02/10] Linux Kernel Markers, architecture independent code.

Mathieu Desnoyers
2007-05-10T19:46:50Z

* Alexey Dobriyan (adobriyan@gmail.com) wrote:
> On Thu, May 10, 2007 at 09:12:41AM -0400, Mathieu Desnoyers wrote:
> > Linux Kernel Markers - Architecture Independant Code fix 2
> >
> > Fix trivial SMP bug in list_modules.
>
> > --- linux-2.6-lttng.orig/kernel/module.c 2007-05-10 08:51:02.000000000 -0400
> > +++ linux-2.6-lttng/kernel/module.c 2007-05-10 08:51:06.000000000 -0400
> > @@ -2657,13 +2657,16 @@
> > /* Enumerate loaded modules */
> > struct list_head *i;
> > struct module *mod;
> > - unsigned long refcount = 0;
> > + unsigned long refcount;
> > + int cpu;
> >
> > mutex_lock(&module_mutex);
> > list_for_each(i, &modules) {
> > mod = list_entry(i, struct module, list);
> > + refcount = 0;
> > #ifdef CONFIG_MODULE_UNLOAD
> > - refcount = local_read(&mod->ref[0].count);
> > + for_each_online_cpu(cpu)
> > + refcount += local_read(&mod->ref[cpu].count);
> > #endif //CONFIG_MODULE_UNLOAD
>
> Still wrong: module_get on cpu X, cpu X hot unplugged. There is
> module_refcount() for you.

Ok, fixing. thanks.

--
Mathieu Desnoyers
Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68