[v1] lockdep: suggest the fix for "lockdep bfs error:-1" on print_bfs_bug

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

Posted by Luis Claudio R. Goncalves 1 month, 2 weeks ago

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@redhat.com>
---
 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)
+		pr_warn("Increase LOCKDEP_CIRCULAR_QUEUE_BITS to avoid this warning:\n");
+
 	WARN(1, "lockdep bfs error:%d\n", ret);
 }
 
-- 
2.45.2

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

Posted by Boqun Feng 1 month, 1 week ago

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@redhat.com>
> ---
>  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.

Reviewed-by: Boqun Feng <boqun.feng@gmail.com>

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
>

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

Posted by Luis Claudio R. Goncalves 1 month, 1 week ago

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@redhat.com>
> > ---
> >  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

> Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
> 
> 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---

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

Posted by Waiman Long 1 month, 1 week ago

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@redhat.com>
>>> ---
>>>   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@redhat.com>

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

Cheers,
Longman

>
>> Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
>>
>> 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---
>