Commit bb9d3d56 authored by Rusty Russell's avatar Rusty Russell
Browse files

module: better OOPS and lockdep coverage for loading modules 



If we put the module in the linked list *before* calling into to, we
get the module name and functions in the OOPS (is_module_address can
find the module).  It also helps lockdep in a similar way.

Acked-and-tested-by: default avatarJoern Engel <joern@lazybastard.org>
Tested-by: default avatarErez Zadok <ezk@cs.sunysb.edu>
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent efa5345e

kernel/module.c

+20 −18
Original line number Diff line number Diff line
@@ -1293,6 +1293,17 @@ static void mod_kobject_remove(struct module *mod) 
	kobject_put(&mod->mkobj.kobj);

}



/*

 * link the module with the whole machine is stopped with interrupts off

 * - this defends against kallsyms not taking locks

 */

static int __link_module(void *_mod)

{

	struct module *mod = _mod;

	list_add(&mod->list, &modules);

	return 0;

}



/*

 * unlink the module with the whole machine is stopped with interrupts off

 * - this defends against kallsyms not taking locks
@@ -2035,6 +2046,11 @@ static struct module *load_module(void __user *umod, 
		printk(KERN_WARNING "%s: Ignoring obsolete parameters\n",

		       mod->name);



	/* Now sew it into the lists so we can get lockdep and oops

         * info during argument parsing.  Noone should access us, since

         * strong_try_module_get() will fail. */

	stop_machine_run(__link_module, mod, NR_CPUS);



	/* Size of section 0 is 0, so this works well if no params */

	err = parse_args(mod->name, mod->args,

			 (struct kernel_param *)
@@ -2043,7 +2059,7 @@ static struct module *load_module(void __user *umod, 
			 / sizeof(struct kernel_param),

			 NULL);

	if (err < 0)

		goto arch_cleanup;

		goto unlink;



	err = mod_sysfs_setup(mod,

			      (struct kernel_param *)
@@ -2051,7 +2067,7 @@ static struct module *load_module(void __user *umod, 
			      sechdrs[setupindex].sh_size

			      / sizeof(struct kernel_param));

	if (err < 0)

		goto arch_cleanup;

		goto unlink;

	add_sect_attrs(mod, hdr->e_shnum, secstrings, sechdrs);

	add_notes_attrs(mod, hdr->e_shnum, secstrings, sechdrs);
@@ -2066,7 +2082,8 @@ static struct module *load_module(void __user *umod, 
	/* Done! */

	return mod;



 arch_cleanup:

 unlink:

	stop_machine_run(__unlink_module, mod, NR_CPUS);

	module_arch_cleanup(mod);

 cleanup:

	kobject_del(&mod->mkobj.kobj);
@@ -2091,17 +2108,6 @@ static struct module *load_module(void __user *umod, 
	goto free_hdr;

}



/*

 * link the module with the whole machine is stopped with interrupts off

 * - this defends against kallsyms not taking locks

 */

static int __link_module(void *_mod)

{

	struct module *mod = _mod;

	list_add(&mod->list, &modules);

	return 0;

}



/* This is where the real work happens */

asmlinkage long

sys_init_module(void __user *umod,
@@ -2126,10 +2132,6 @@ sys_init_module(void __user *umod, 
		return PTR_ERR(mod);

	}



	/* Now sew it into the lists.  They won't access us, since

           strong_try_module_get() will fail. */

	stop_machine_run(__link_module, mod, NR_CPUS);



	/* Drop lock so they can recurse */

	mutex_unlock(&module_mutex);

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