linux-kernel - [PATCH 16/27] locking/lockdep: Stop using RCU primitives to access all_lock

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20181128234325.110011-17-bvanassche@acm.org>
Date:   Wed, 28 Nov 2018 15:43:14 -0800
From:   Bart Van Assche <bvanassche@....org>
To:     mingo@...hat.com
Cc:     peterz@...radead.org, tj@...nel.org, johannes.berg@...el.com,
        linux-kernel@...r.kernel.org, Bart Van Assche <bvanassche@....org>
Subject: [PATCH 16/27] locking/lockdep: Stop using RCU primitives to access all_lock_classes

Due to the previous patch all code that accesses the 'all_lock_classes'
list holds the graph lock. Hence use regular list primitives instead of
their RCU variants to access this list.

Signed-off-by: Bart Van Assche <bvanassche@....org>
---
 kernel/locking/lockdep.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index ab6abe52e974..96fc8e92c2a6 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -626,7 +626,8 @@ static int static_obj(void *obj)
 
 /*
  * To make lock name printouts unique, we calculate a unique
- * class->name_version generation counter:
+ * class->name_version generation counter. The caller must hold the graph
+ * lock.
  */
 static int count_matching_names(struct lock_class *new_class)
 {
@@ -636,7 +637,7 @@ static int count_matching_names(struct lock_class *new_class)
 	if (!new_class->name)
 		return 0;
 
-	list_for_each_entry_rcu(class, &all_lock_classes, lock_entry) {
+	list_for_each_entry(class, &all_lock_classes, lock_entry) {
 		if (new_class->key - new_class->subclass == class->key)
 			return class->name_version;
 		if (class->name && !strcmp(class->name, new_class->name))
@@ -801,7 +802,7 @@ register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
 	/*
 	 * Add it to the global list of classes:
 	 */
-	list_add_tail_rcu(&class->lock_entry, &all_lock_classes);
+	list_add_tail(&class->lock_entry, &all_lock_classes);
 
 	if (verbose(class)) {
 		graph_unlock();
@@ -4120,6 +4121,9 @@ void lockdep_reset(void)
 	raw_local_irq_restore(flags);
 }
 
+/*
+ * Remove all references to a lock class. The caller must hold the graph lock.
+ */
 static void zap_class(struct lock_class *class)
 {
 	int i;
@@ -4136,7 +4140,7 @@ static void zap_class(struct lock_class *class)
 	 * Unhash the class and remove it from the all_lock_classes list:
 	 */
 	hlist_del_rcu(&class->hash_entry);
-	list_del_rcu(&class->lock_entry);
+	list_del(&class->lock_entry);
 
 	RCU_INIT_POINTER(class->key, NULL);
 	RCU_INIT_POINTER(class->name, NULL);
-- 
2.20.0.rc0.387.gc7a69e6b6c-goog