Commit-ID: 4bf508621855613ca2ac782f70c3171e0e8bb011
Gitweb: https://git.kernel.org/tip/4bf508621855613ca2ac782f70c3171e0e8bb011
Author: Bart Van Assche <bvanassche@xxxxxxx>
AuthorDate: Thu, 14 Feb 2019 15:00:52 -0800
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Thu, 28 Feb 2019 07:55:46 +0100
locking/lockdep: Verify whether lock objects are small enough to be used as class keys
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Johannes Berg <johannes@xxxxxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Waiman Long <longman@xxxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: johannes.berg@xxxxxxxxx
Cc: tj@xxxxxxxxxx
Link: https://lkml.kernel.org/r/20190214230058.196511-18-bvanassche@xxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
kernel/locking/lockdep.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 630be9ac6253..84427441824e 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -758,6 +758,17 @@ static bool assign_lock_key(struct lockdep_map *lock)
{
unsigned long can_addr, addr = (unsigned long)lock;
+#ifdef __KERNEL__
+ /*
+ * lockdep_free_key_range() assumes that struct lock_class_key
+ * objects do not overlap. Since we use the address of lock
+ * objects as class key for static objects, check whether the
+ * size of lock_class_key objects does not exceed the size of
+ * the smallest lock object.
+ */
+ BUILD_BUG_ON(sizeof(struct lock_class_key) > sizeof(raw_spinlock_t));
+#endif
+
if (__is_kernel_percpu_address(addr, &can_addr))
lock->key = (void *)can_addr;
else if (__is_module_percpu_address(addr, &can_addr))
|