[dm-devel] [PATCH] block: add a bi_error field to struct bio

[Christoph Hellwig]

On Wed, Jun 10, 2015 at 12:50:54PM +1000, Neil Brown wrote:
> This introduces a use-after-free.  put_buf(r1_bio) can  result in bio_put on
> 'bio'.
> It is safe to move the put_buf call after the md_done_sync(), but it is
> probably best to leave the 'update' variable as it.  i.e. Just change:
> 
> -	int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
> +	int uptodate = !bio->bi_error;
> 
> 
> I can't see any other problems with the md changes.

Thanks, I'll keep the local uptodate variable for now.