The commit is pushed to "branch-rh9-5.14.0-427.37.1.vz9.78.x-ovz" and will
appear at g...@bitbucket.org:openvz/vzkernel.git
after rh9-5.14.0-427.37.1.vz9.78.4
------>
commit ea734486119b98aa0a5f4bbb8117af839fcaf587
Author: Pavel Tikhomirov <ptikhomi...@virtuozzo.com>
Date: Wed Nov 6 17:20:30 2024 +0800
vhost-blk: fix bio allocation failure on excess bio vector count
The bio_alloc() function does not allow to allocate bio-s with more than
BIO_MAX_VECS bio vectors. Currently we give to it the nr_vecs argument
equal to the number of pages in all iovecs of the processed request,
which can be much bigger than BIO_MAX_VECS (256), this is incorrect and
leads to the bug in biovec_slab(): "kernel BUG at block/bio.c:62!".
Fix it by restricting the nr_vecs argument properly by bio_max_segs()
helper, also let's decrease pages_nr_total by the number of already
processed pages, so that we can use bio with less vectors when possible.
Fixes: 17bfe6e0400da ("drivers/vhost: vhost-blk accelerator for virtio-blk
guests")
https://virtuozzo.atlassian.net/browse/VSTOR-94596
Signed-off-by: Pavel Tikhomirov <ptikhomi...@virtuozzo.com>
Feature: vhost-blk: in-kernel accelerator for virtio-blk guests
---
drivers/vhost/blk.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/vhost/blk.c b/drivers/vhost/blk.c
index cd8d71c28bbd..d77e5fc494de 100644
--- a/drivers/vhost/blk.c
+++ b/drivers/vhost/blk.c
@@ -297,7 +297,7 @@ static int vhost_blk_bio_make(struct vhost_blk_req *req,
len = iov_len;
while (!bio || !bio_add_page(bio, page, len, off)) {
- bio = bio_alloc(bdev, pages_nr_total,
+ bio = bio_alloc(bdev,
bio_max_segs(pages_nr_total),
req->bi_opf, GFP_KERNEL);
if (!bio)
goto fail;
@@ -309,6 +309,7 @@ static int vhost_blk_bio_make(struct vhost_blk_req *req,
iov_base += len;
iov_len -= len;
+ pages_nr_total--;
pos = (iov_base & VHOST_BLK_SECTOR_MASK) + iov_len;
req->sector += pos >> VHOST_BLK_SECTOR_BITS;
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