Re: [PATCH] block2mtd lockdep_init_map warning

Jörn Engel
2008-01-07T10:26:34Z

On Mon, 7 January 2008 11:05:26 +0100, Peter Zijlstra wrote:
>
> Would something like this work for people?

Looks a lot better than what I thought of. However, does the #ifdef
within is_module_address() make sense when afaict lockdep is the only
caller of that function? Looks as if the whole function should be made
conditional or none of it.

> Not-Yet-Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
> ---
> Index: linux-2.6/include/linux/sched.h
> ===================================================================
> --- linux-2.6.orig/include/linux/sched.h
> +++ linux-2.6/include/linux/sched.h
> @@ -1160,6 +1160,7 @@ struct task_struct {
> int lockdep_depth;
> struct held_lock held_locks[MAX_LOCK_DEPTH];
> unsigned int lockdep_recursion;
> + struct module *loading_module;
> #endif
>
> /* journalling filesystem info */
> Index: linux-2.6/kernel/module.c
> ===================================================================
> --- linux-2.6.orig/kernel/module.c
> +++ linux-2.6/kernel/module.c
> @@ -2023,6 +2023,9 @@ static struct module *load_module(void _
> printk(KERN_WARNING "%s: Ignoring obsolete parameters\n",
> mod->name);
>
> +#ifdef CONFIG_LOCKDEP
> + current->loading_module = mod;
> +#endif
> /* Size of section 0 is 0, so this works well if no params */
> err = parse_args(mod->name, mod->args,
> (struct kernel_param *)
> @@ -2030,6 +2033,9 @@ static struct module *load_module(void _
> sechdrs[setupindex].sh_size
> / sizeof(struct kernel_param),
> NULL);
> +#ifdef CONFIG_LOCKDEP
> + current->loading_module = NULL
> +#endif
> if (err < 0)
> goto arch_cleanup;
>
> @@ -2454,6 +2460,17 @@ int is_module_address(unsigned long addr
> }
> }
>
> +#ifdef CONFIG_LOCKDEP
> + if (current->loading_module) {
> + mod = current->loading_module;
> + if (within(addr, mod->module_init, mod->init_text_size)
> + || within(addr, mod->module_core, mod->core_text_size)) {
> + preempt_enable();
> + return 1;
> + }
> + }
> +#endif
> +
> preempt_enable();
>
> return 0;
>
>
>

Jörn

--
I don't understand it. Nobody does.
-- Richard P. Feynman