The following commit has been merged into the locking/core branch of tip: Commit-ID: 8ca5e9186d367807336c5a40a086aef163c18800 Gitweb: https://git.kernel.org/tip/8ca5e9186d367807336c5a40a086aef163c18800 Author: Waiman Long <longman@xxxxxxxxxx> AuthorDate: Fri, 14 Feb 2025 14:52:42 -05:00 Committer: Boqun Feng <boqun.feng@xxxxxxxxx> CommitterDate: Sun, 23 Feb 2025 18:24:46 -08:00 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: Marco Elver <elver@xxxxxxxxxx> Signed-off-by: Waiman Long <longman@xxxxxxxxxx> Reviewed-by: Marco Elver <elver@xxxxxxxxxx> Reviewed-by: Andrey Konovalov <andreyknvl@xxxxxxxxx> Signed-off-by: Boqun Feng <boqun.feng@xxxxxxxxx> Link: https://lore.kernel.org/r/20250214195242.2480920-1-longman@xxxxxxxxxx --- kernel/locking/lockdep.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 8436f01..b15757e 100644 --- a/kernel/locking/lockdep.c +++ b/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> @@ -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) {
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