diff options
Diffstat (limited to 'kernel/module.c')
| -rw-r--r-- | kernel/module.c | 24 |
1 files changed, 23 insertions, 1 deletions
diff --git a/kernel/module.c b/kernel/module.c index dd02b40cd891..36023bce008f 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -23,6 +23,7 @@ * Fix sys_init_module race, Andrew Morton <andrewm@uow.edu.au> Oct 2000 * http://www.uwsg.iu.edu/hypermail/linux/kernel/0008.3/0379.html * Replace xxx_module_symbol with inter_module_xxx. Keith Owens <kaos@ocs.com.au> Oct 2000 + * Add a module list lock for kernel fault race fixing. Alan Cox <alan@redhat.com> * * This source is covered by the GNU GPL, the same as all kernel sources. */ @@ -65,6 +66,17 @@ static struct list_head ime_list = LIST_HEAD_INIT(ime_list); static spinlock_t ime_lock = SPIN_LOCK_UNLOCKED; static int kmalloc_failed; +/* + * This lock prevents modifications that might race the kernel fault + * fixups. It does not prevent reader walks that the modules code + * does. The kernel lock does that. + * + * Since vmalloc fault fixups occur in any context this lock is taken + * irqsave at all times. + */ + +spinlock_t modlist_lock = SPIN_LOCK_UNLOCKED; + /** * inter_module_register - register a new set of inter module data. * @im_name: an arbitrary string to identify the data, must be unique @@ -283,6 +295,7 @@ sys_create_module(const char *name_user, size_t size) char *name; long namelen, error; struct module *mod; + unsigned long flags; if (!capable(CAP_SYS_MODULE)) return -EPERM; @@ -306,14 +319,16 @@ sys_create_module(const char *name_user, size_t size) memset(mod, 0, sizeof(*mod)); mod->size_of_struct = sizeof(*mod); - mod->next = module_list; mod->name = (char *)(mod + 1); mod->size = size; memcpy((char*)(mod+1), name, namelen+1); put_mod_name(name); + spin_lock_irqsave(&modlist_lock, flags); + mod->next = module_list; module_list = mod; /* link it in */ + spin_unlock_irqrestore(&modlist_lock, flags); error = (long) mod; goto err0; @@ -628,6 +643,7 @@ sys_delete_module(const char *name_user) /* Do automatic reaping */ restart: something_changed = 0; + for (mod = module_list; mod != &kernel_module; mod = next) { next = mod->next; spin_lock(&unload_lock); @@ -651,10 +667,13 @@ restart: spin_unlock(&unload_lock); } } + if (something_changed) goto restart; + for (mod = module_list; mod != &kernel_module; mod = mod->next) mod->flags &= ~MOD_JUST_FREED; + error = 0; out: unlock_kernel(); @@ -1018,6 +1037,7 @@ free_module(struct module *mod, int tag_freed) { struct module_ref *dep; unsigned i; + unsigned long flags; /* Let the module clean up. */ @@ -1041,6 +1061,7 @@ free_module(struct module *mod, int tag_freed) /* And from the main module list. */ + spin_lock_irqsave(&modlist_lock, flags); if (mod == module_list) { module_list = mod->next; } else { @@ -1049,6 +1070,7 @@ free_module(struct module *mod, int tag_freed) continue; p->next = mod->next; } + spin_unlock_irqrestore(&modlist_lock, flags); /* And free the memory. */ |