* FAILED: patch "[PATCH] VDUSE: avoid leaking information to userspace" failed to apply to 5.15-stable tree
@ 2026-07-20 12:13 gregkh
2026-07-23 1:16 ` [PATCH 5.15.y 1/4] vduse: Use fixed 4KB bounce pages for non-4KB page size Sasha Levin
0 siblings, 1 reply; 5+ messages in thread
From: gregkh @ 2026-07-20 12:13 UTC (permalink / raw)
To: jasowangio, eperezma, jasowang, mst, xieyongji; +Cc: stable
The patch below does not apply to the 5.15-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-5.15.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-challenge-grimacing-a682@gregkh' --subject-prefix 'PATCH 5.15.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;
^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH 5.15.y 1/4] vduse: Use fixed 4KB bounce pages for non-4KB page size
2026-07-20 12:13 FAILED: patch "[PATCH] VDUSE: avoid leaking information to userspace" failed to apply to 5.15-stable tree gregkh
@ 2026-07-23 1:16 ` Sasha Levin
2026-07-23 1:16 ` [PATCH 5.15.y 2/4] vduse: remove unused vaddr parameter of vduse_domain_free_coherent Sasha Levin
` (2 more replies)
0 siblings, 3 replies; 5+ messages in thread
From: Sasha Levin @ 2026-07-23 1:16 UTC (permalink / raw)
To: stable; +Cc: Sheng Zhao, Michael S. Tsirkin, Sasha Levin
From: Sheng Zhao <sheng.zhao@bytedance.com>
[ Upstream commit 3fc3068e7247c94dec08e93fea422a1bb649bfe5 ]
The allocation granularity of bounce pages is PAGE_SIZE. This may cause
even small IO requests to occupy an entire bounce page exclusively. The
kind of memory waste will be more significant when PAGE_SIZE is larger
than 4KB (e.g. arm64 with 64KB pages).
So, optimize it by using fixed 4KB bounce maps and iova allocation
granularity. A single IO request occupies at least a 4KB bounce page
instead of the entire memory page of PAGE_SIZE.
Signed-off-by: Sheng Zhao <sheng.zhao@bytedance.com>
Message-Id: <20250925113516.60305-1-sheng.zhao@bytedance.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Stable-dep-of: 9c1523803445 ("VDUSE: avoid leaking information to userspace")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/vdpa/vdpa_user/iova_domain.c | 64 +++++++++++++++++++---------
drivers/vdpa/vdpa_user/iova_domain.h | 5 +++
2 files changed, 50 insertions(+), 19 deletions(-)
diff --git a/drivers/vdpa/vdpa_user/iova_domain.c b/drivers/vdpa/vdpa_user/iova_domain.c
index 0678c251419736..35363ca0b49bd4 100644
--- a/drivers/vdpa/vdpa_user/iova_domain.c
+++ b/drivers/vdpa/vdpa_user/iova_domain.c
@@ -103,19 +103,38 @@ void vduse_domain_clear_map(struct vduse_iova_domain *domain,
static int vduse_domain_map_bounce_page(struct vduse_iova_domain *domain,
u64 iova, u64 size, u64 paddr)
{
- struct vduse_bounce_map *map;
+ struct vduse_bounce_map *map, *head_map;
+ struct page *tmp_page;
u64 last = iova + size - 1;
while (iova <= last) {
- map = &domain->bounce_maps[iova >> PAGE_SHIFT];
+ /*
+ * When PAGE_SIZE is larger than 4KB, multiple adjacent bounce_maps will
+ * point to the same memory page of PAGE_SIZE. Since bounce_maps originate
+ * from IO requests, we may not be able to guarantee that the orig_phys
+ * values of all IO requests within the same 64KB memory page are contiguous.
+ * Therefore, we need to store them separately.
+ *
+ * Bounce pages are allocated on demand. As a result, it may occur that
+ * multiple bounce pages corresponding to the same 64KB memory page attempt
+ * to allocate memory simultaneously, so we use cmpxchg to handle this
+ * concurrency.
+ */
+ map = &domain->bounce_maps[iova >> BOUNCE_MAP_SHIFT];
if (!map->bounce_page) {
- map->bounce_page = alloc_page(GFP_ATOMIC);
- if (!map->bounce_page)
- return -ENOMEM;
+ head_map = &domain->bounce_maps[(iova & PAGE_MASK) >> BOUNCE_MAP_SHIFT];
+ if (!head_map->bounce_page) {
+ tmp_page = alloc_page(GFP_ATOMIC);
+ if (!tmp_page)
+ return -ENOMEM;
+ if (cmpxchg(&head_map->bounce_page, NULL, tmp_page))
+ __free_page(tmp_page);
+ }
+ map->bounce_page = head_map->bounce_page;
}
map->orig_phys = paddr;
- paddr += PAGE_SIZE;
- iova += PAGE_SIZE;
+ paddr += BOUNCE_MAP_SIZE;
+ iova += BOUNCE_MAP_SIZE;
}
return 0;
}
@@ -127,12 +146,17 @@ static void vduse_domain_unmap_bounce_page(struct vduse_iova_domain *domain,
u64 last = iova + size - 1;
while (iova <= last) {
- map = &domain->bounce_maps[iova >> PAGE_SHIFT];
+ map = &domain->bounce_maps[iova >> BOUNCE_MAP_SHIFT];
map->orig_phys = INVALID_PHYS_ADDR;
- iova += PAGE_SIZE;
+ iova += BOUNCE_MAP_SIZE;
}
}
+static unsigned int offset_in_bounce_page(dma_addr_t addr)
+{
+ return (addr & ~BOUNCE_MAP_MASK);
+}
+
static void do_bounce(phys_addr_t orig, void *addr, size_t size,
enum dma_data_direction dir)
{
@@ -163,7 +187,7 @@ static void vduse_domain_bounce(struct vduse_iova_domain *domain,
enum dma_data_direction dir)
{
struct vduse_bounce_map *map;
- unsigned int offset;
+ unsigned int offset, head_offset;
void *addr;
size_t sz;
@@ -171,15 +195,16 @@ static void vduse_domain_bounce(struct vduse_iova_domain *domain,
return;
while (size) {
- map = &domain->bounce_maps[iova >> PAGE_SHIFT];
- offset = offset_in_page(iova);
- sz = min_t(size_t, PAGE_SIZE - offset, size);
+ map = &domain->bounce_maps[iova >> BOUNCE_MAP_SHIFT];
+ head_offset = offset_in_page(iova);
+ offset = offset_in_bounce_page(iova);
+ sz = min_t(size_t, BOUNCE_MAP_SIZE - offset, size);
if (WARN_ON(!map->bounce_page ||
map->orig_phys == INVALID_PHYS_ADDR))
return;
- addr = page_address(map->bounce_page) + offset;
+ addr = page_address(map->bounce_page) + head_offset;
do_bounce(map->orig_phys + offset, addr, sz, dir);
size -= sz;
iova += sz;
@@ -214,7 +239,7 @@ vduse_domain_get_bounce_page(struct vduse_iova_domain *domain, u64 iova)
struct page *page = NULL;
spin_lock(&domain->iotlb_lock);
- map = &domain->bounce_maps[iova >> PAGE_SHIFT];
+ map = &domain->bounce_maps[iova >> BOUNCE_MAP_SHIFT];
if (!map->bounce_page)
goto out;
@@ -232,7 +257,7 @@ vduse_domain_free_bounce_pages(struct vduse_iova_domain *domain)
struct vduse_bounce_map *map;
unsigned long pfn, bounce_pfns;
- bounce_pfns = domain->bounce_size >> PAGE_SHIFT;
+ bounce_pfns = domain->bounce_size >> BOUNCE_MAP_SHIFT;
for (pfn = 0; pfn < bounce_pfns; pfn++) {
map = &domain->bounce_maps[pfn];
@@ -242,7 +267,8 @@ vduse_domain_free_bounce_pages(struct vduse_iova_domain *domain)
if (!map->bounce_page)
continue;
- __free_page(map->bounce_page);
+ if (!((pfn << BOUNCE_MAP_SHIFT) & ~PAGE_MASK))
+ __free_page(map->bounce_page);
map->bounce_page = NULL;
}
}
@@ -489,7 +515,7 @@ vduse_domain_create(unsigned long iova_limit, size_t bounce_size)
struct vduse_bounce_map *map;
unsigned long pfn, bounce_pfns;
- bounce_pfns = PAGE_ALIGN(bounce_size) >> PAGE_SHIFT;
+ bounce_pfns = PAGE_ALIGN(bounce_size) >> BOUNCE_MAP_SHIFT;
if (iova_limit <= bounce_size)
return NULL;
@@ -520,7 +546,7 @@ vduse_domain_create(unsigned long iova_limit, size_t bounce_size)
domain->file = file;
spin_lock_init(&domain->iotlb_lock);
init_iova_domain(&domain->stream_iovad,
- PAGE_SIZE, IOVA_START_PFN);
+ BOUNCE_MAP_SIZE, IOVA_START_PFN);
init_iova_domain(&domain->consistent_iovad,
PAGE_SIZE, bounce_pfns);
diff --git a/drivers/vdpa/vdpa_user/iova_domain.h b/drivers/vdpa/vdpa_user/iova_domain.h
index 2722d9b8e21aff..b87dac1137d7c7 100644
--- a/drivers/vdpa/vdpa_user/iova_domain.h
+++ b/drivers/vdpa/vdpa_user/iova_domain.h
@@ -19,6 +19,11 @@
#define INVALID_PHYS_ADDR (~(phys_addr_t)0)
+#define BOUNCE_MAP_SHIFT 12
+#define BOUNCE_MAP_SIZE (1 << BOUNCE_MAP_SHIFT)
+#define BOUNCE_MAP_MASK (~(BOUNCE_MAP_SIZE - 1))
+#define BOUNCE_MAP_ALIGN(addr) (((addr) + BOUNCE_MAP_SIZE - 1) & ~(BOUNCE_MAP_SIZE - 1))
+
struct vduse_bounce_map {
struct page *bounce_page;
u64 orig_phys;
--
2.53.0
^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH 5.15.y 2/4] vduse: remove unused vaddr parameter of vduse_domain_free_coherent
2026-07-23 1:16 ` [PATCH 5.15.y 1/4] vduse: Use fixed 4KB bounce pages for non-4KB page size Sasha Levin
@ 2026-07-23 1:16 ` Sasha Levin
2026-07-23 1:16 ` [PATCH 5.15.y 3/4] vduse: take out allocations from vduse_dev_alloc_coherent Sasha Levin
2026-07-23 1:16 ` [PATCH 5.15.y 4/4] VDUSE: avoid leaking information to userspace Sasha Levin
2 siblings, 0 replies; 5+ messages in thread
From: Sasha Levin @ 2026-07-23 1:16 UTC (permalink / raw)
To: stable; +Cc: Eugenio Pérez, Michael S. Tsirkin, Sasha Levin
From: Eugenio Pérez <eperezma@redhat.com>
[ Upstream commit 766e1749c0ef6a09651be9b8a8283d508c322b58 ]
We will modify the function in next patches so let's clean it first.
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20260119143306.1818855-9-eperezma@redhat.com>
Stable-dep-of: 9c1523803445 ("VDUSE: avoid leaking information to userspace")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/vdpa/vdpa_user/iova_domain.c | 3 +--
drivers/vdpa/vdpa_user/iova_domain.h | 3 +--
drivers/vdpa/vdpa_user/vduse_dev.c | 2 +-
3 files changed, 3 insertions(+), 5 deletions(-)
diff --git a/drivers/vdpa/vdpa_user/iova_domain.c b/drivers/vdpa/vdpa_user/iova_domain.c
index 35363ca0b49bd4..d16ec4fcd797b5 100644
--- a/drivers/vdpa/vdpa_user/iova_domain.c
+++ b/drivers/vdpa/vdpa_user/iova_domain.c
@@ -416,8 +416,7 @@ void *vduse_domain_alloc_coherent(struct vduse_iova_domain *domain,
}
void vduse_domain_free_coherent(struct vduse_iova_domain *domain, size_t size,
- void *vaddr, dma_addr_t dma_addr,
- unsigned long attrs)
+ dma_addr_t dma_addr, unsigned long attrs)
{
struct iova_domain *iovad = &domain->consistent_iovad;
struct vhost_iotlb_map *map;
diff --git a/drivers/vdpa/vdpa_user/iova_domain.h b/drivers/vdpa/vdpa_user/iova_domain.h
index b87dac1137d7c7..940778b60318fa 100644
--- a/drivers/vdpa/vdpa_user/iova_domain.h
+++ b/drivers/vdpa/vdpa_user/iova_domain.h
@@ -61,8 +61,7 @@ void *vduse_domain_alloc_coherent(struct vduse_iova_domain *domain,
gfp_t flag, unsigned long attrs);
void vduse_domain_free_coherent(struct vduse_iova_domain *domain, size_t size,
- void *vaddr, dma_addr_t dma_addr,
- unsigned long attrs);
+ dma_addr_t dma_addr, unsigned long attrs);
void vduse_domain_reset_bounce_map(struct vduse_iova_domain *domain);
diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
index 4684d4756b427e..1f594e4db71eb1 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -793,7 +793,7 @@ static void vduse_dev_free_coherent(struct device *dev, size_t size,
struct vduse_dev *vdev = dev_to_vduse(dev);
struct vduse_iova_domain *domain = vdev->domain;
- vduse_domain_free_coherent(domain, size, vaddr, dma_addr, attrs);
+ vduse_domain_free_coherent(domain, size, dma_addr, attrs);
}
static size_t vduse_dev_max_mapping_size(struct device *dev)
--
2.53.0
^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH 5.15.y 3/4] vduse: take out allocations from vduse_dev_alloc_coherent
2026-07-23 1:16 ` [PATCH 5.15.y 1/4] vduse: Use fixed 4KB bounce pages for non-4KB page size Sasha Levin
2026-07-23 1:16 ` [PATCH 5.15.y 2/4] vduse: remove unused vaddr parameter of vduse_domain_free_coherent Sasha Levin
@ 2026-07-23 1:16 ` Sasha Levin
2026-07-23 1:16 ` [PATCH 5.15.y 4/4] VDUSE: avoid leaking information to userspace Sasha Levin
2 siblings, 0 replies; 5+ messages in thread
From: Sasha Levin @ 2026-07-23 1:16 UTC (permalink / raw)
To: stable; +Cc: Eugenio Pérez, Jason Wang, Michael S. Tsirkin, Sasha Levin
From: Eugenio Pérez <eperezma@redhat.com>
[ Upstream commit 489d76520612abf9a4ede4344349105406c91a73 ]
The function vduse_dev_alloc_coherent will be called under rwlock in
next patches. Make it out of the lock to avoid increasing its fail
rate.
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20260119143306.1818855-10-eperezma@redhat.com>
Stable-dep-of: 9c1523803445 ("VDUSE: avoid leaking information to userspace")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/vdpa/vdpa_user/iova_domain.c | 24 +++++++-----------------
drivers/vdpa/vdpa_user/iova_domain.h | 5 ++---
drivers/vdpa/vdpa_user/vduse_dev.c | 14 ++++++++++----
3 files changed, 19 insertions(+), 24 deletions(-)
diff --git a/drivers/vdpa/vdpa_user/iova_domain.c b/drivers/vdpa/vdpa_user/iova_domain.c
index d16ec4fcd797b5..26f3fb5e0b0677 100644
--- a/drivers/vdpa/vdpa_user/iova_domain.c
+++ b/drivers/vdpa/vdpa_user/iova_domain.c
@@ -381,17 +381,15 @@ void vduse_domain_unmap_page(struct vduse_iova_domain *domain,
vduse_domain_free_iova(iovad, dma_addr, size);
}
-void *vduse_domain_alloc_coherent(struct vduse_iova_domain *domain,
- size_t size, dma_addr_t *dma_addr,
- gfp_t flag, unsigned long attrs)
+dma_addr_t vduse_domain_alloc_coherent(struct vduse_iova_domain *domain,
+ size_t size, void *orig)
{
struct iova_domain *iovad = &domain->consistent_iovad;
unsigned long limit = domain->iova_limit;
dma_addr_t iova = vduse_domain_alloc_iova(iovad, size, limit);
- void *orig = alloc_pages_exact(size, flag);
- if (!iova || !orig)
- goto err;
+ if (!iova)
+ return DMA_MAPPING_ERROR;
spin_lock(&domain->iotlb_lock);
if (vduse_iotlb_add_range(domain, (u64)iova, (u64)iova + size - 1,
@@ -402,17 +400,12 @@ void *vduse_domain_alloc_coherent(struct vduse_iova_domain *domain,
}
spin_unlock(&domain->iotlb_lock);
- *dma_addr = iova;
+ return iova;
- return orig;
err:
- *dma_addr = DMA_MAPPING_ERROR;
- if (orig)
- free_pages_exact(orig, size);
- if (iova)
- vduse_domain_free_iova(iovad, iova, size);
+ vduse_domain_free_iova(iovad, iova, size);
- return NULL;
+ return DMA_MAPPING_ERROR;
}
void vduse_domain_free_coherent(struct vduse_iova_domain *domain, size_t size,
@@ -421,7 +414,6 @@ void vduse_domain_free_coherent(struct vduse_iova_domain *domain, size_t size,
struct iova_domain *iovad = &domain->consistent_iovad;
struct vhost_iotlb_map *map;
struct vdpa_map_file *map_file;
- phys_addr_t pa;
spin_lock(&domain->iotlb_lock);
map = vhost_iotlb_itree_first(domain->iotlb, (u64)dma_addr,
@@ -433,12 +425,10 @@ void vduse_domain_free_coherent(struct vduse_iova_domain *domain, size_t size,
map_file = (struct vdpa_map_file *)map->opaque;
fput(map_file->file);
kfree(map_file);
- pa = map->addr;
vhost_iotlb_map_free(domain->iotlb, map);
spin_unlock(&domain->iotlb_lock);
vduse_domain_free_iova(iovad, dma_addr, size);
- free_pages_exact(phys_to_virt(pa), size);
}
static vm_fault_t vduse_domain_mmap_fault(struct vm_fault *vmf)
diff --git a/drivers/vdpa/vdpa_user/iova_domain.h b/drivers/vdpa/vdpa_user/iova_domain.h
index 940778b60318fa..e8a196c4c8f889 100644
--- a/drivers/vdpa/vdpa_user/iova_domain.h
+++ b/drivers/vdpa/vdpa_user/iova_domain.h
@@ -56,9 +56,8 @@ void vduse_domain_unmap_page(struct vduse_iova_domain *domain,
dma_addr_t dma_addr, size_t size,
enum dma_data_direction dir, unsigned long attrs);
-void *vduse_domain_alloc_coherent(struct vduse_iova_domain *domain,
- size_t size, dma_addr_t *dma_addr,
- gfp_t flag, unsigned long attrs);
+dma_addr_t vduse_domain_alloc_coherent(struct vduse_iova_domain *domain,
+ size_t size, void *orig);
void vduse_domain_free_coherent(struct vduse_iova_domain *domain, size_t size,
dma_addr_t dma_addr, unsigned long attrs);
diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
index 1f594e4db71eb1..8f05d1bfdb1076 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -772,18 +772,23 @@ static void *vduse_dev_alloc_coherent(struct device *dev, size_t size,
{
struct vduse_dev *vdev = dev_to_vduse(dev);
struct vduse_iova_domain *domain = vdev->domain;
- unsigned long iova;
void *addr;
*dma_addr = DMA_MAPPING_ERROR;
- addr = vduse_domain_alloc_coherent(domain, size,
- (dma_addr_t *)&iova, flag, attrs);
+
+ addr = alloc_pages_exact(size, flag);
if (!addr)
return NULL;
- *dma_addr = (dma_addr_t)iova;
+ *dma_addr = vduse_domain_alloc_coherent(domain, size, addr);
+ if (*dma_addr == DMA_MAPPING_ERROR)
+ goto err;
return addr;
+
+err:
+ free_pages_exact(addr, size);
+ return NULL;
}
static void vduse_dev_free_coherent(struct device *dev, size_t size,
@@ -794,6 +799,7 @@ static void vduse_dev_free_coherent(struct device *dev, size_t size,
struct vduse_iova_domain *domain = vdev->domain;
vduse_domain_free_coherent(domain, size, dma_addr, attrs);
+ free_pages_exact(vaddr, size);
}
static size_t vduse_dev_max_mapping_size(struct device *dev)
--
2.53.0
^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH 5.15.y 4/4] VDUSE: avoid leaking information to userspace
2026-07-23 1:16 ` [PATCH 5.15.y 1/4] vduse: Use fixed 4KB bounce pages for non-4KB page size Sasha Levin
2026-07-23 1:16 ` [PATCH 5.15.y 2/4] vduse: remove unused vaddr parameter of vduse_domain_free_coherent Sasha Levin
2026-07-23 1:16 ` [PATCH 5.15.y 3/4] vduse: take out allocations from vduse_dev_alloc_coherent Sasha Levin
@ 2026-07-23 1:16 ` Sasha Levin
2 siblings, 0 replies; 5+ messages in thread
From: Sasha Levin @ 2026-07-23 1:16 UTC (permalink / raw)
To: stable
Cc: Jason Wang, Xie Yongji, Eugenio Pérez, Michael S. Tsirkin,
Sasha Levin
From: Jason Wang <jasowang@redhat.com>
[ Upstream commit 9c1523803445ee0348f62b77793266dd981596e0 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/vdpa/vdpa_user/iova_domain.c | 2 +-
drivers/vdpa/vdpa_user/vduse_dev.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/vdpa/vdpa_user/iova_domain.c b/drivers/vdpa/vdpa_user/iova_domain.c
index 26f3fb5e0b0677..783319f1607619 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 8f05d1bfdb1076..ce84b0fb8428d3 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -776,7 +776,7 @@ static void *vduse_dev_alloc_coherent(struct device *dev, size_t size,
*dma_addr = DMA_MAPPING_ERROR;
- addr = alloc_pages_exact(size, flag);
+ addr = alloc_pages_exact(size, flag | __GFP_ZERO);
if (!addr)
return NULL;
--
2.53.0
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2026-07-20 12:13 FAILED: patch "[PATCH] VDUSE: avoid leaking information to userspace" failed to apply to 5.15-stable tree gregkh
2026-07-23 1:16 ` [PATCH 5.15.y 1/4] vduse: Use fixed 4KB bounce pages for non-4KB page size Sasha Levin
2026-07-23 1:16 ` [PATCH 5.15.y 2/4] vduse: remove unused vaddr parameter of vduse_domain_free_coherent Sasha Levin
2026-07-23 1:16 ` [PATCH 5.15.y 3/4] vduse: take out allocations from vduse_dev_alloc_coherent Sasha Levin
2026-07-23 1:16 ` [PATCH 5.15.y 4/4] VDUSE: avoid leaking information to userspace Sasha Levin
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