On 04/19/2013 01:52 AM, Tejun Heo wrote:
> Hello, Wanlong.
> 
> On Thu, Apr 18, 2013 at 10:45:10PM +0800, Wanlong Gao wrote:
>> OK, but I should capture it tomorrow morning because this remote machine has already panicked
>> and need hard reboot.
> 
> Can you please apply the following patch when you try the next time
> and report the kernel log?  It should prevent the oops from happening
> and dump information on at least who are the involved parties.

Here attached.

Thanks,
Wanlong Gao

> 
> Thanks.
> 
> diff --git a/block/blk-core.c b/block/blk-core.c
> index 074b758..d5efebe 100644
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
> @@ -150,6 +150,8 @@ void blk_rq_init(struct request_queue *q, struct request *rq)
>  }
>  EXPORT_SYMBOL(blk_rq_init);
>  
> +
> +
>  static void req_bio_endio(struct request *rq, struct bio *bio,
>  			  unsigned int nbytes, int error)
>  {
> @@ -174,8 +176,15 @@ static void req_bio_endio(struct request *rq, struct bio *bio,
>  		bio_integrity_advance(bio, nbytes);
>  
>  	/* don't actually finish bio if it's part of flush sequence */
> -	if (bio->bi_size == 0 && !(rq->cmd_flags & REQ_FLUSH_SEQ))
> +	if (bio->bi_size == 0 && !(rq->cmd_flags & REQ_FLUSH_SEQ)) {
> +		if (bio->bi_bdev && (unsigned long)bio->bi_bdev < 4096) {
> +			printk_ratelimited("XXX req_bio_endio: queue %s bio=%p bi_bdev=%p bi_end_io=%pf\n",
> +					   (rq->q && rq->q->backing_dev_info.dev) ?
> +					   dev_name(rq->q->backing_dev_info.dev) : "<unknown>",
> +					   bio, bio->bi_bdev, bio->bi_end_io);
> +		}
>  		bio_endio(bio, error);
> +	}
>  }
>  
>  void blk_dump_rq_flags(struct request *rq, char *msg)
> diff --git a/fs/bio.c b/fs/bio.c
> index bb5768f..da64e5a 100644
> --- a/fs/bio.c
> +++ b/fs/bio.c
> @@ -1428,7 +1428,10 @@ void bio_endio(struct bio *bio, int error)
>  	else if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
>  		error = -EIO;
>  
> -	trace_block_bio_complete(bio, error);
> +	if (bio->bi_bdev && (unsigned long)bio->bi_bdev < 4096)
> +		printk_ratelimited("XXX bio_endio: skipping TP for %p\n", bio);
> +	else
> +		trace_block_bio_complete(bio, error);
>  
>  	if (bio->bi_end_io)
>  		bio->bi_end_io(bio, error);
>