FAILED: patch "[PATCH] VDUSE: avoid leaking information to userspace" failed to apply to 6.1-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 6.1-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 9c1523803445ee0348f62b77793266dd981596e0
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026072042-splendor-serotonin-4456@gregkh' --subject-prefix 'PATCH 6.1.y' 'HEAD^..'

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 9c1523803445ee0348f62b77793266dd981596e0 Mon Sep 17 00:00:00 2001
From: Jason Wang <jasowangio@gmail.com>
Date: Fri, 30 Jan 2026 13:07:50 +0800
Subject: [PATCH] VDUSE: avoid leaking information to userspace
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

The bounceing is not necessarily page aligned, so current VDUSE can
leak kernel information through mapping bounce pages to
userspace. Allocate bounce pages with __GFP_ZERO to avoid leaking
information to userspace.

Fixes: 8c773d53fb7b ("vduse: Implement an MMU-based software IOTLB")
Cc: stable@vger.kernel.org
Signed-off-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Xie Yongji <xieyongji@bytedance.com>
Reviewed-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-ID: <20260130050750.4050-1-jasowang@redhat.com>

diff --git a/drivers/vdpa/vdpa_user/iova_domain.c b/drivers/vdpa/vdpa_user/iova_domain.c
index 806cec32c4bc..4dc76c0d0d13 100644
--- a/drivers/vdpa/vdpa_user/iova_domain.c
+++ b/drivers/vdpa/vdpa_user/iova_domain.c
@@ -124,7 +124,7 @@ static int vduse_domain_map_bounce_page(struct vduse_iova_domain *domain,
 		if (!map->bounce_page) {
 			head_map = &domain->bounce_maps[(iova & PAGE_MASK) >> BOUNCE_MAP_SHIFT];
 			if (!head_map->bounce_page) {
-				tmp_page = alloc_page(GFP_ATOMIC);
+				tmp_page = alloc_page(GFP_ATOMIC | __GFP_ZERO);
 				if (!tmp_page)
 					return -ENOMEM;
 				if (cmpxchg(&head_map->bounce_page, NULL, tmp_page))
diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
index 81409a5bb09b..9ebbe6541157 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -999,7 +999,7 @@ static void *vduse_dev_alloc_coherent(union virtio_map token, size_t size,
 	if (!token.group)
 		return NULL;
 
-	addr = alloc_pages_exact(size, flag);
+	addr = alloc_pages_exact(size, flag | __GFP_ZERO);
 	if (!addr)
 		return NULL;