This reverts commit 78139c94dc8c96a478e67dab3bee84dc6eccb5fd. We don't
protect device IOTLB with vq mutex, which will lead e.g use after free
for device IOTLB entries. And since we've switched to use
mutex_trylock() in previous patch, it's safe to revert it without
having deadlock.
Fixes: commit 78139c94dc8c ("net: vhost: lock the vqs one by one")
Cc: Tonghao Zhang <xiangxia.m.yue@xxxxxxxxx>
Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
---
drivers/vhost/vhost.c | 21 +++++++++++++++++----
1 file changed, 17 insertions(+), 4 deletions(-)
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 5915f240275a..55e5aa662ad5 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -295,11 +295,8 @@ static void vhost_vq_meta_reset(struct vhost_dev *d)
{
int i;
- for (i = 0; i < d->nvqs; ++i) {
- mutex_lock(&d->vqs[i]->mutex);
+ for (i = 0; i < d->nvqs; ++i)
__vhost_vq_meta_reset(d->vqs[i]);
- mutex_unlock(&d->vqs[i]->mutex);
- }
}
static void vhost_vq_reset(struct vhost_dev *dev,
@@ -895,6 +892,20 @@ static inline void __user *__vhost_get_user(struct vhost_virtqueue *vq,
#define vhost_get_used(vq, x, ptr) \
vhost_get_user(vq, x, ptr, VHOST_ADDR_USED)
+static void vhost_dev_lock_vqs(struct vhost_dev *d)
+{
+ int i = 0;
+ for (i = 0; i < d->nvqs; ++i)
+ mutex_lock_nested(&d->vqs[i]->mutex, i);
+}
+
+static void vhost_dev_unlock_vqs(struct vhost_dev *d)
+{
+ int i = 0;
+ for (i = 0; i < d->nvqs; ++i)
+ mutex_unlock(&d->vqs[i]->mutex);
+}
+
static int vhost_new_umem_range(struct vhost_umem *umem,
u64 start, u64 size, u64 end,
u64 userspace_addr, int perm)
@@ -976,6 +987,7 @@ static int vhost_process_iotlb_msg(struct vhost_dev *dev,
int ret = 0;
mutex_lock(&dev->mutex);
+ vhost_dev_lock_vqs(dev);
switch (msg->type) {
case VHOST_IOTLB_UPDATE:
if (!dev->iotlb) {
@@ -1009,6 +1021,7 @@ static int vhost_process_iotlb_msg(struct vhost_dev *dev,
break;
}
+ vhost_dev_unlock_vqs(dev);
mutex_unlock(&dev->mutex);
return ret;
--
2.17.1
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