Revert "module: drop the lock while waiting for module to complete initialization."
This reverts commit 480b02df3aa9f07d1c7df0cd8be7a5ca73893455, since
Rafael reports that it causes occasional kernel paging request faults in
load_module().
Dropping the module lock and re-taking it deep in the call-chain is
definitely not the right thing to do. That just turns the mutex from a
lock into a "random non-locking data structure" that doesn't actually
protect what it's supposed to protect.
Requested-and-tested-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Brandon Philips <brandon@ifup.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/module.c b/kernel/module.c
index 625985e..333fbcc 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -563,26 +563,33 @@
struct module_use *use;
int no_warn, err;
- if (b == NULL || already_uses(a, b))
- return 0;
+ if (b == NULL || already_uses(a, b)) return 1;
/* If we're interrupted or time out, we fail. */
- err = strong_try_module_get(b);
+ if (wait_event_interruptible_timeout(
+ module_wq, (err = strong_try_module_get(b)) != -EBUSY,
+ 30 * HZ) <= 0) {
+ printk("%s: gave up waiting for init of module %s.\n",
+ a->name, b->name);
+ return 0;
+ }
+
+ /* If strong_try_module_get() returned a different error, we fail. */
if (err)
- return err;
+ return 0;
DEBUGP("Allocating new usage for %s.\n", a->name);
use = kmalloc(sizeof(*use), GFP_ATOMIC);
if (!use) {
printk("%s: out of memory loading\n", a->name);
module_put(b);
- return -ENOMEM;
+ return 0;
}
use->module_which_uses = a;
list_add(&use->list, &b->modules_which_use_me);
no_warn = sysfs_create_link(b->holders_dir, &a->mkobj.kobj, a->name);
- return 0;
+ return 1;
}
EXPORT_SYMBOL_GPL(use_module);
@@ -875,7 +882,7 @@
int use_module(struct module *a, struct module *b)
{
- return strong_try_module_get(b);
+ return strong_try_module_get(b) == 0;
}
EXPORT_SYMBOL_GPL(use_module);
@@ -1046,39 +1053,17 @@
struct module *owner;
const struct kernel_symbol *sym;
const unsigned long *crc;
- DEFINE_WAIT(wait);
- int err;
- long timeleft = 30 * HZ;
-again:
sym = find_symbol(name, &owner, &crc,
!(mod->taints & (1 << TAINT_PROPRIETARY_MODULE)), true);
- if (!sym)
- return NULL;
-
- if (!check_version(sechdrs, versindex, name, mod, crc, owner))
- return NULL;
-
- prepare_to_wait(&module_wq, &wait, TASK_INTERRUPTIBLE);
- err = use_module(mod, owner);
- if (likely(!err) || err != -EBUSY || signal_pending(current)) {
- finish_wait(&module_wq, &wait);
- return err ? NULL : sym;
+ /* use_module can fail due to OOM,
+ or module initialization or unloading */
+ if (sym) {
+ if (!check_version(sechdrs, versindex, name, mod, crc, owner)
+ || !use_module(mod, owner))
+ sym = NULL;
}
-
- /* Module is still loading. Drop lock and wait. */
- mutex_unlock(&module_mutex);
- timeleft = schedule_timeout(timeleft);
- mutex_lock(&module_mutex);
- finish_wait(&module_wq, &wait);
-
- /* Module might be gone entirely, or replaced. Re-lookup. */
- if (timeleft)
- goto again;
-
- printk(KERN_WARNING "%s: gave up waiting for init of module %s.\n",
- mod->name, owner->name);
- return NULL;
+ return sym;
}
/*