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commitd7fe143cb1upstream. 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@syzkaller.appspotmail.com> Fixes:de8f5e4f2d("lockdep: Introduce wait-type checks") Cc: stable@vger.kernel.org Signed-off-by: Ahmed Ehab <bottaawesome633@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/lkml/20240824221031.7751-1-bottaawesome633@gmail.com/ Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>