Merge: locking/lockdep: Disable KASAN instrumentation of lockdep.c

MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-9/-/merge_requests/6507

JIRA: https://issues.redhat.com/browse/RHEL-81997
MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-9/-/merge_requests/6507

KASAN and LOCKDEP are the two major performance hitters in the debug
kernel. Disabling KASAN instrumentation in the LOCKDEP code can regain
some of the lost performance back. A targeted KASAN memory check is
still done in the lock_acquire() function to catch memory error, if any.

Signed-off-by: Waiman Long <longman@redhat.com>

Approved-by: Phil Auld <pauld@redhat.com>
Approved-by: Wander Lairson Costa <wander@redhat.com>
Approved-by: CKI KWF Bot <cki-ci-bot+kwf-gitlab-com@redhat.com>

Merged-by: Augusto Caringi <acaringi@redhat.com>

Author: caringi

kernel/locking/Makefile

@@ -5,7 +5,8 @@ KCOV_INSTRUMENT		:= n
 
 obj-y += mutex.o semaphore.o rwsem.o percpu-rwsem.o
 
-# Avoid recursion lockdep -> sanitizer -> ... -> lockdep.
+# Avoid recursion lockdep -> sanitizer -> ... -> lockdep & improve performance.
+KASAN_SANITIZE_lockdep.o := n
 KCSAN_SANITIZE_lockdep.o := n
 
 ifdef CONFIG_FUNCTION_TRACER

kernel/locking/lockdep.c

@@ -57,6 +57,7 @@
 #include <linux/lockdep.h>
 #include <linux/context_tracking.h>
 #include <linux/console.h>
+#include <linux/kasan.h>
 
 #include <asm/sections.h>
 
@@ -5738,6 +5739,14 @@ void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
 	if (!debug_locks)
 		return;
 
+	/*
+	 * As KASAN instrumentation is disabled and lock_acquire() is usually
+	 * the first lockdep call when a task tries to acquire a lock, add
+	 * kasan_check_byte() here to check for use-after-free and other
+	 * memory errors.
+	 */
+	kasan_check_byte(lock);
+
 	if (unlikely(!lockdep_enabled())) {
 		/* XXX allow trylock from NMI ?!? */
 		if (lockdep_nmi() && !trylock) {