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module: better OOPS and lockdep coverage for loading modules

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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: Joern Engel <joern@lazybastard.org>
Tested-by: Erez Zadok <ezk@cs.sunysb.edu>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell 2008-01-29 17:13:21 -05:00
parent efa5345e39
commit bb9d3d56e7
1 changed files with 20 additions and 18 deletions
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38
kernel/module.c
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@ -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);