[PATCH 5.10 257/459] locking/lockdep: Avoid creating new name string literals in lockdep_set_subclass()

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



5.10-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ahmed Ehab <bottaawesome633@xxxxxxxxx>

commit d7fe143cb115076fed0126ad8cf5ba6c3e575e43 upstream.

Syzbot reports a problem that a warning will be triggered while
searching a lock class in look_up_lock_class().

The cause of the issue is that a new name is created and used by
lockdep_set_subclass() instead of using the existing one. This results
in a lock instance has a different name pointer than previous registered
one stored in lock class, and WARN_ONCE() is triggered because of that
in look_up_lock_class().

To fix this, change lockdep_set_subclass() to use the existing name
instead of a new one. Hence, no new name will be created by
lockdep_set_subclass(). Hence, the warning is avoided.

[boqun: Reword the commit log to state the correct issue]

Reported-by: <syzbot+7f4a6f7f7051474e40ad@xxxxxxxxxxxxxxxxxxxxxxxxx>
Fixes: de8f5e4f2dc1f ("lockdep: Introduce wait-type checks")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Ahmed Ehab <bottaawesome633@xxxxxxxxx>
Signed-off-by: Boqun Feng <boqun.feng@xxxxxxxxx>
Link: https://lore.kernel.org/lkml/20240824221031.7751-1-bottaawesome633@xxxxxxxxx/
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 include/linux/lockdep.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -233,7 +233,7 @@ static inline void lockdep_init_map(stru
 			      (lock)->dep_map.lock_type)
 
 #define lockdep_set_subclass(lock, sub)					\
-	lockdep_init_map_type(&(lock)->dep_map, #lock, (lock)->dep_map.key, sub,\
+	lockdep_init_map_type(&(lock)->dep_map, (lock)->dep_map.name, (lock)->dep_map.key, sub,\
 			      (lock)->dep_map.wait_type_inner,		\
 			      (lock)->dep_map.wait_type_outer,		\
 			      (lock)->dep_map.lock_type)






[Index of Archives]     [Linux Kernel]     [Kernel Development Newbies]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite Hiking]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux