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authorRusty Russell <rusty@rustcorp.com.au>2012-09-28 14:31:03 +0930
committerRusty Russell <rusty@rustcorp.com.au>2012-09-28 14:31:03 +0930
commit6f13909f4fe9652f189b462c6c98767309000321 (patch)
tree0b56b6817caea8d81c46bbbfe575cd4729ca4a23
parent786d35d45cc40b2a51a18f73e14e135d47fdced7 (diff)
downloadop-kernel-dev-6f13909f4fe9652f189b462c6c98767309000321.zip
op-kernel-dev-6f13909f4fe9652f189b462c6c98767309000321.tar.gz
module: fix symbol waiting when module fails before init
We use resolve_symbol_wait(), which blocks if the module containing the symbol is still loading. However: 1) The module_wq we use is only woken after calling the modules' init function, but there are other failure paths after the module is placed in the linked list where we need to do the same thing. 2) wake_up() only wakes one waiter, and our waitqueue is shared by all modules, so we need to wake them all. 3) wake_up_all() doesn't imply a memory barrier: I feel happier calling it after we've grabbed and dropped the module_mutex, not just after the state assignment. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
-rw-r--r--kernel/module.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/kernel/module.c b/kernel/module.c
index 7f2ee45f..63cf6e7 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2959,7 +2959,7 @@ static struct module *load_module(void __user *umod,
/* Unlink carefully: kallsyms could be walking list. */
list_del_rcu(&mod->list);
module_bug_cleanup(mod);
-
+ wake_up_all(&module_wq);
ddebug:
dynamic_debug_remove(info.debug);
unlock:
@@ -3034,7 +3034,7 @@ SYSCALL_DEFINE3(init_module, void __user *, umod,
blocking_notifier_call_chain(&module_notify_list,
MODULE_STATE_GOING, mod);
free_module(mod);
- wake_up(&module_wq);
+ wake_up_all(&module_wq);
return ret;
}
if (ret > 0) {
@@ -3046,9 +3046,8 @@ SYSCALL_DEFINE3(init_module, void __user *, umod,
dump_stack();
}
- /* Now it's a first class citizen! Wake up anyone waiting for it. */
+ /* Now it's a first class citizen! */
mod->state = MODULE_STATE_LIVE;
- wake_up(&module_wq);
blocking_notifier_call_chain(&module_notify_list,
MODULE_STATE_LIVE, mod);
@@ -3071,6 +3070,7 @@ SYSCALL_DEFINE3(init_module, void __user *, umod,
mod->init_ro_size = 0;
mod->init_text_size = 0;
mutex_unlock(&module_mutex);
+ wake_up_all(&module_wq);
return 0;
}
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