diff --git a/module/os/linux/zfs/abd_os.c b/module/os/linux/zfs/abd_os.c
index 2a31111bb3..3774a9c3de 100644
--- a/module/os/linux/zfs/abd_os.c
+++ b/module/os/linux/zfs/abd_os.c
@@ -1055,12 +1055,16 @@ bio_map(struct bio *bio, void *buf_ptr, unsigned int bio_size)
 			is_split = B_FALSE;
 		}
 		else if (offset != 0) {
+			ASSERT(!is_split);
+
 			/*
 			 * This is a split page, so we need to ensure that we
 			 * have room for the tail within this bio.
 			 */
-			if ((i + 1) == bio->bi_max_vecs)
+			if ((i + 1) == bio->bi_max_vecs) {
+				cmn_err(CE_NOTE, "bio_map: avoided misalignment! bio %p", bio);
 				break;
+			}
 
 			/* Take up to the end of the page */
 			size = PAGE_SIZE - offset;
@@ -1094,6 +1098,9 @@ bio_map(struct bio *bio, void *buf_ptr, unsigned int bio_size)
 		offset = 0;
 	}
 
+	if (is_split)
+		cmn_err(CE_WARN, "bio_map: still split at exit! bio %p size %lu vecs %lu", bio, BIO_BI_SIZE(bio), bio->bi_vcnt);
+
 	return (bio_size);
 }
 
@@ -1167,12 +1174,16 @@ abd_bio_map_off(struct bio *bio, abd_t *abd,
 			is_split = B_FALSE;
 		}
 		else if (pgoff != 0) {
+			ASSERT(!is_split);
+
 			/*
 			 * This is a split page, so we need to ensure that we
 			 * have room for the tail within this bio.
 			 */
-			if ((i + 1) == bio->bi_max_vecs)
+			if ((i + 1) == bio->bi_max_vecs) {
+				cmn_err(CE_NOTE, "abd_bio_map_off: avoided misalignment! bio %p", bio);
 				break;
+			}
 
 			/* Take up to the end of the page */
 			len = PAGE_SIZE - pgoff;
@@ -1196,6 +1207,9 @@ abd_bio_map_off(struct bio *bio, abd_t *abd,
 		abd_iter_advance(&aiter, len);
 	}
 
+	if (is_split)
+		cmn_err(CE_WARN, "abd_bio_map_off: still split at exit! bio %p size %lu vecs %lu", bio, BIO_BI_SIZE(bio), bio->bi_vcnt);
+
 	return (io_size);
 }
 
diff --git a/module/os/linux/zfs/vdev_disk.c b/module/os/linux/zfs/vdev_disk.c
index 0ed1a112f5..0108b42478 100644
--- a/module/os/linux/zfs/vdev_disk.c
+++ b/module/os/linux/zfs/vdev_disk.c
@@ -693,6 +693,14 @@ retry:
 		bio_size = abd_bio_map_off(dr->dr_bio[i], zio->io_abd,
 		    bio_size, abd_offset);
 
+		if (BIO_BI_SIZE(dr->dr_bio[i]) & 0xfff) {
+			cmn_err(CE_WARN, "misaligned bio! zio %p bio %p offset %lu size %lu vecs %lu", zio, dr->dr_bio[i], bio_offset, BIO_BI_SIZE(dr->dr_bio[i]), dr->dr_bio[i]->bi_vcnt);
+			for (int bi = 0; bi < dr->dr_bio[i]->bi_vcnt; bi++) {
+				struct bio_vec *bv = &dr->dr_bio[i]->bi_io_vec[bi];
+				cmn_err(CE_WARN, "    %02x: off %lu len %lu", bi, bv->bv_offset, bv->bv_len);
+			}
+		}
+
 		/* Advance in buffer and construct another bio if needed */
 		abd_offset += BIO_BI_SIZE(dr->dr_bio[i]);
 		bio_offset += BIO_BI_SIZE(dr->dr_bio[i]);