[PATCH v3 21/24] locking/lockdep: Verify whether lock objects are small enough to be used as class keys

[Bart Van Assche]

Cc: Peter Zijlstra 
Cc: Waiman Long 
Cc: Johannes Berg 
Signed-off-by: Bart Van Assche 
---
 kernel/locking/lockdep.c | 9 +
 1 file changed, 9 insertions(+)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 8c69516b1283..a47357d3dca7 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -727,6 +727,15 @@ static bool assign_lock_key(struct lockdep_map *lock)
 {
unsigned long can_addr, addr = (unsigned long)lock;
 
+   /*
+* 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));
+
if (__is_kernel_percpu_address(addr, _addr))
lock->key = (void *)can_addr;
else if (__is_module_percpu_address(addr, _addr))
-- 
2.20.0.rc2.403.gdbc3b29805-goog

[PATCH v3 21/24] locking/lockdep: Verify whether lock objects are small enough to be used as class keys

[Bart Van Assche]

Cc: Peter Zijlstra 
Cc: Waiman Long 
Cc: Johannes Berg 
Signed-off-by: Bart Van Assche 
---
 kernel/locking/lockdep.c | 9 +
 1 file changed, 9 insertions(+)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 8c69516b1283..a47357d3dca7 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -727,6 +727,15 @@ static bool assign_lock_key(struct lockdep_map *lock)
 {
unsigned long can_addr, addr = (unsigned long)lock;
 
+   /*
+* 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));
+
if (__is_kernel_percpu_address(addr, _addr))
lock->key = (void *)can_addr;
else if (__is_module_percpu_address(addr, _addr))
-- 
2.20.0.rc2.403.gdbc3b29805-goog