Re: [PATCH] lockdep: suggest the fix for "lockdep bfs error:-1" on print_bfs_bug

[Waiman Long]

On 7/29/24 12:53, Luis Claudio R. Goncalves wrote:
> On Fri, Jul 26, 2024 at 02:24:28PM -0700, Boqun Feng wrote:
> > On Thu, Jul 25, 2024 at 03:45:57PM -0300, Luis Claudio R. Goncalves wrote:
> > > When lockdep fails while performing the Breadth-first-search operation
> > > due to lack of memory, hint that increasing the value of the configuration
> > > switch LOCKDEP_CIRCULAR_QUEUE_BITS should fix the warning.
> > >
> > > Preface the scary bactrace with the suggestion:
> > >
> > >      [  163.849242] Increase LOCKDEP_CIRCULAR_QUEUE_BITS to avoid this warning:
> > >      [  163.849248] ------------[ cut here ]------------
> > >      [  163.849250] lockdep bfs error:-1
> > >      [  163.849263] WARNING: CPU: 24 PID: 2454 at kernel/locking/lockdep.c:2091 print_bfs_bug+0x27/0x40
> > >      ...
> > >
> > > Signed-off-by: Luis Claudio R. Goncalves <lgoncalv@xxxxxxxxxx>
> > > ---
> > >   kernel/locking/lockdep.c | 3 +++
> > >   1 file changed, 3 insertions(+)
> > >
> > > diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
> > > index 58c88220a478a..1cf6d9fdddc9c 100644
> > > --- a/kernel/locking/lockdep.c
> > > +++ b/kernel/locking/lockdep.c
> > > @@ -2067,6 +2067,9 @@ static noinline void print_bfs_bug(int ret)
> > >   	/*
> > >   	 * Breadth-first-search failed, graph got corrupted?
> > >   	 */
> > > +	if (ret  == BFS_EQUEUEFULL)
> > This line has an extra space after "ret", but otherwise it looks fine.
> Should I send a v2 of the patch with the extra whitespace removed?
>
> Luis

Yes, you should. Other than the extra space, the patch looks good to me too.

Reviewed-by: Waiman Long <longman@xxxxxxxxxx>

You can also add our review-by tags in your v2 patch.

Cheers,
Longman

> > Reviewed-by: Boqun Feng <boqun.feng@xxxxxxxxx>
> >
> > Regards,
> > Boqun
> >
> > > +		pr_warn("Increase LOCKDEP_CIRCULAR_QUEUE_BITS to avoid this warning:\n");
> > > +
> > >   	WARN(1, "lockdep bfs error:%d\n", ret);
> > >   }
> > >   
> > > --
> > > 2.45.2
> ---end quoted text---