5.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jason Wang jasowang@redhat.com
[ Upstream commit b4ba1207d45adaafa2982c035898b36af2d3e518 ]
This patch fails vhost_add_used_n() early when __vhost_add_used() fails to make sure used idx is not updated with stale used ring information.
Reported-by: Eugenio Pérez eperezma@redhat.com Signed-off-by: Jason Wang jasowang@redhat.com Message-Id: 20250714084755.11921-2-jasowang@redhat.com Signed-off-by: Michael S. Tsirkin mst@redhat.com Tested-by: Lei Yang leiyang@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/vhost/vhost.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index 061af5dc92e6..973e079025a9 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -2421,6 +2421,9 @@ int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads, } r = __vhost_add_used_n(vq, heads, count);
+ if (r < 0) + return r; + /* Make sure buffer is written before we update index. */ smp_wmb(); if (vhost_put_used_idx(vq)) {