1 files changed, 25 insertions, 15 deletions

diff --git a/kernel/module/main.c b/kernel/module/main.c
index 6f4ec857bdef..71396e297499 100644
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -3104,7 +3104,7 @@ static bool idempotent(struct idempotent *u, const void *cookie)
 	struct idempotent *existing;
 	bool first;
 
-	u->ret = 0;
+	u->ret = -EINTR;
 	u->cookie = cookie;
 	init_completion(&u->complete);
 
@@ -3140,7 +3140,7 @@ static int idempotent_complete(struct idempotent *u, int ret)
 	hlist_for_each_entry_safe(pos, next, head, entry) {
 		if (pos->cookie != cookie)
 			continue;
-		hlist_del(&pos->entry);
+		hlist_del_init(&pos->entry);
 		pos->ret = ret;
 		complete(&pos->complete);
 	}
@@ -3148,6 +3148,28 @@ static int idempotent_complete(struct idempotent *u, int ret)
 	return ret;
 }
 
+/*
+ * Wait for the idempotent worker.
+ *
+ * If we get interrupted, we need to remove ourselves from the
+ * the idempotent list, and the completion may still come in.
+ *
+ * The 'idem_lock' protects against the race, and 'idem.ret' was
+ * initialized to -EINTR and is thus always the right return
+ * value even if the idempotent work then completes between
+ * the wait_for_completion and the cleanup.
+ */
+static int idempotent_wait_for_completion(struct idempotent *u)
+{
+	if (wait_for_completion_interruptible(&u->complete)) {
+		spin_lock(&idem_lock);
+		if (!hlist_unhashed(&u->entry))
+			hlist_del(&u->entry);
+		spin_unlock(&idem_lock);
+	}
+	return u->ret;
+}
+
 static int init_module_from_file(struct file *f, const char __user * uargs, int flags)
 {
 	struct load_info info = { };
@@ -3191,20 +3213,8 @@ static int idempotent_init_module(struct file *f, const char __user * uargs, int
 
 	/*
 	 * Somebody else won the race and is loading the module.
-	 *
-	 * We have to wait for it forever, since our 'idem' is
-	 * on the stack and the list entry stays there until
-	 * completed (but we could fix it under the idem_lock)
-	 *
-	 * It's also unclear what a real timeout might be,
-	 * but we could maybe at least make this killable
-	 * and remove the idem entry in that case?
 	 */
-	for (;;) {
-		if (wait_for_completion_timeout(&idem.complete, 10*HZ))
-			return idem.ret;
-		pr_warn_once("module '%pD' taking a long time to load", f);
-	}
+	return idempotent_wait_for_completion(&idem);
 }
 
 SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags)