Re: [next-20260108]kernel BUG at drivers/scsi/scsi_lib.c:1173!

[Ming Lei]

On Thu, Jan 08, 2026 at 09:56:39PM -0800, Christoph Hellwig wrote:
> I've seen the same when running xfstests on xfs, and bisected it to:
> 
> commit ee623c892aa59003fca173de0041abc2ccc2c72d
> Author: Ming Lei <ming.lei@xxxxxxxxxx>
> Date:   Wed Dec 31 11:00:55 2025 +0800
> 
>     block: use bvec iterator helper for bio_may_need_split()
> 

Hi Christoph and Venkat Rao Bagalkote,

Unfortunately I can't duplicate the issue in my environment, can you test
the following patch?

diff --git a/block/blk.h b/block/blk.h
index 98f4dfd4ec75..980eef1f5690 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -380,7 +380,7 @@ static inline bool bio_may_need_split(struct bio *bio,
                return true;
 
        bv = __bvec_iter_bvec(bio->bi_io_vec, bio->bi_iter);
-       if (bio->bi_iter.bi_size > bv->bv_len)
+       if (bio->bi_iter.bi_size > bv->bv_len - bio->bi_iter.bi_bvec_done)
                return true;
        return bv->bv_len + bv->bv_offset > lim->max_fast_segment_size;
 }


Thanks,
Ming