From 7b813f30a6dd485d872d606307e65dbb99d41737 Mon Sep 17 00:00:00 2001 From: Jason Wang Date: Thu, 13 Dec 2018 10:53:39 +0800 Subject: [PATCH] Revert "net: vhost: lock the vqs one by one" This reverts commit 827c8ca547b26e5b31964d29c5ae79729750c8f8. 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 827c8ca547b2 ("net: vhost: lock the vqs one by one") Cc: Tonghao Zhang Acked-by: Michael S. Tsirkin Signed-off-by: Jason Wang Signed-off-by: David S. Miller --- 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 5915f240275a9..55e5aa662ad59 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; -- 2.39.5