Re: [bug report] BUG: kernel NULL pointer dereference, address: 0000000000000048

[Yu Kuai <yukuai1@huaweicloud.com>]

Hi,

在 2023/05/10 14:39, Ming Lei 写道:
> On Wed, May 10, 2023 at 12:05:07PM +0800, Guangwu Zhang wrote:
>> HI,
>> after apply your patch[1], the system will panic after reboot.

This is werid, I just reporduce this problem in my VM, and I verified
this patch can fix the problem.

Anyway, Ming's patch looks better, you can try it.

Thanks,
Kuai
>>
> 
> Maybe you can try the following patch?
> 
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index f6dad0886a2f..d84174a7e997 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -1303,7 +1303,7 @@ void blk_execute_rq_nowait(struct request *rq, bool at_head)
>           * device, directly accessing the plug instead of using blk_mq_plug()
>           * should not have any consequences.
>           */
> -       if (current->plug && !at_head) {
> +       if (current->plug && !at_head && rq->bio) {
>                  blk_add_rq_to_plug(current->plug, rq);
>                  return;
>          }
> 
> 
> thanks,
> Ming
> 
> .
>