Re: [PATCH v2 1/2] ext4: Forcing subclasses to have same name pointer as their parent class

[Boqun Feng]

On Mon, Jul 15, 2024 at 12:39:45AM +0300, ahmed Ehab wrote:
> Ok, I will.
> I just put ext4 because the syzkaller bug was mentioned in the ext4
> subsystem.
> Thanks,
> Ahmed
> 

Please avoid top-posting. And 

> On Mon, Jul 15, 2024 at 12:22 AM Waiman Long <longman@xxxxxxxxxx> wrote:
> 
> > On 7/14/24 01:14, botta633 wrote:
> > > From: Ahmed Ehab <bottaawesome633@xxxxxxxxx>
> > >
> > > Preventing lockdep_set_subclass from creating a new instance of the
> > > string literal. Hence, we will always have the same class->name among
> > > parent and subclasses. This prevents kernel panics when looking up a
> > > lock class while comparing class locks and class names.
> > >
> > > Reported-by: <syzbot+7f4a6f7f7051474e40ad@xxxxxxxxxxxxxxxxxxxxxxxxx>
> > > Fixes: fd5e3f5fe27

please add the title of the commit here as well, e.g.

Fixes: <sha1> ("<title>")

see

	https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f7ce5eb2cb7993e4417642ac28713a063123461f	

for example.

Regards,
Boqun

> > > Cc: <stable@xxxxxxxxxxxxxxx>
> > > Signed-off-by: Ahmed Ehab <bottaawesome633@xxxxxxxxx>
> > > ---
> > >   include/linux/lockdep.h | 2 +-
> > >   1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
> > > index 08b0d1d9d78b..df8fa5929de7 100644
> > > --- a/include/linux/lockdep.h
> > > +++ b/include/linux/lockdep.h
> > > @@ -173,7 +173,7 @@ static inline void lockdep_init_map(struct
> > lockdep_map *lock, const char *name,
> > >                             (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)
> >
> > ext4 is a filesystem. It has nothing to do with locking/lockdep. Could
> > you resend the patches with the proper prefix of "lockdep:" or
> > "locking/lockdep:"?
> >
> > Thanks,
> > Longman
> >
> >