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

Boqun Feng
2024-07-26T21:25:01Z

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
>