Commit de4b59d6 authored by Waiman Long's avatar Waiman Long Committed by Ingo Molnar
Browse files

locking/lockdep: Add kasan_check_byte() check in lock_acquire() 



KASAN instrumentation of lockdep has been disabled, as we don't need
KASAN to check the validity of lockdep internal data structures and
incur unnecessary performance overhead. However, the lockdep_map pointer
passed in externally may not be valid (e.g. use-after-free) and we run
the risk of using garbage data resulting in false lockdep reports.

Add kasan_check_byte() call in lock_acquire() for non kernel core data
object to catch invalid lockdep_map and print out a KASAN report before
any lockdep splat, if any.

Suggested-by: default avatarMarco Elver <elver@google.com>
Signed-off-by: default avatarWaiman Long <longman@redhat.com>
Signed-off-by: default avatarBoqun Feng <boqun.feng@gmail.com>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Reviewed-by: default avatarMarco Elver <elver@google.com>
Reviewed-by: default avatarAndrey Konovalov <andreyknvl@gmail.com>
Link: https://lore.kernel.org/r/20250214195242.2480920-1-longman@redhat.com
Link: https://lore.kernel.org/r/20250307232717.1759087-7-boqun.feng@gmail.com
parent ee57ab5a

kernel/locking/lockdep.c

+9 −0
Original line number Diff line number Diff line
@@ -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>
@@ -5830,6 +5831,14 @@ 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) {