kernel/linux.git/drivers/vhost/net.c, branch v5.10.258

vhost_net: fix sleeping with preempt-disabled in vhost_net_busy_poll()

2026-06-01T15:29:41+00:00

[ Upstream commit e08a9fac5cf8c3fecf4755e7e3ac059f78b8f83d ] syzbot reported "sleeping function called from invalid context" in vhost_net_busy_poll(). Commit 030881372460 ("vhost_net: basic polling support") introduced a busy-poll loop and preempt_{disable,enable}() around it, where each iteration calls a sleepable function inside the loop. The purpose of disabling preemption was to keep local_clock()-based timeout accounting on a single CPU, rather than as a requirement of busy-poll itself: https://lore.kernel.org/1448435489-5949-4-git-send-email-jasowang@redhat.com From this perspective, migrate_disable() is sufficient here, so replace preempt_disable() with migrate_disable(), avoiding sleepable accesses from a preempt-disabled context. Fixes: 030881372460 ("vhost_net: basic polling support") Tested-by: syzbot+6985cb8e543ea90ba8ee@syzkaller.appspotmail.com Reported-by: syzbot+6985cb8e543ea90ba8ee@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/69e6a414.050a0220.24bfd3.002d.GAE@google.com/T/ Signed-off-by: Kohei Enju Acked-by: Michael S. Tsirkin Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

vhost/net: Protect ubufs with rcu read lock in vhost_net_ubuf_put()

2025-09-04T12:41:42+00:00

commit dd54bcf86c91a4455b1f95cbc8e9ac91205f3193 upstream. When operating on struct vhost_net_ubuf_ref, the following execution sequence is theoretically possible: CPU0 is finalizing DMA operation CPU1 is doing VHOST_NET_SET_BACKEND // ubufs->refcount == 2 vhost_net_ubuf_put() vhost_net_ubuf_put_wait_and_free(oldubufs) vhost_net_ubuf_put_and_wait() vhost_net_ubuf_put() int r = atomic_sub_return(1, &ubufs->refcount); // r = 1 int r = atomic_sub_return(1, &ubufs->refcount); // r = 0 wait_event(ubufs->wait, !atomic_read(&ubufs->refcount)); // no wait occurs here because condition is already true kfree(ubufs); if (unlikely(!r)) wake_up(&ubufs->wait); // use-after-free This leads to use-after-free on ubufs access. This happens because CPU1 skips waiting for wake_up() when refcount is already zero. To prevent that use a read-side RCU critical section in vhost_net_ubuf_put(), as suggested by Hillf Danton. For this lock to take effect, free ubufs with kfree_rcu(). Cc: stable@vger.kernel.org Fixes: 0ad8b480d6ee9 ("vhost: fix ref cnt checking deadlock") Reported-by: Andrey Ryabinin Suggested-by: Hillf Danton Signed-off-by: Nikolay Kuratov Message-Id: <20250805130917.727332-1-kniv@yandex-team.ru> Signed-off-by: Michael S. Tsirkin Signed-off-by: Greg Kroah-Hartman

vhost/net: Clear the pending messages when the backend is removed

2023-02-15T16:22:11+00:00

[ Upstream commit 9526f9a2b762af16be94a72aca5d65c677d28f50 ] When the vhost iotlb is used along with a guest virtual iommu and the guest gets rebooted, some MISS messages may have been recorded just before the reboot and spuriously executed by the virtual iommu after the reboot. As vhost does not have any explicit reset user API, VHOST_NET_SET_BACKEND looks a reasonable point where to clear the pending messages, in case the backend is removed. Export vhost_clear_msg() and call it in vhost_net_set_backend() when fd == -1. Signed-off-by: Eric Auger Suggested-by: Jason Wang Fixes: 6b1e6cc7855b0 ("vhost: new device IOTLB API") Message-Id: <20230117151518.44725-3-eric.auger@redhat.com> Signed-off-by: Michael S. Tsirkin Signed-off-by: Sasha Levin

Fix double fget() in vhost_net_set_backend()

2022-05-25T07:17:55+00:00

commit fb4554c2232e44d595920f4d5c66cf8f7d13f9bc upstream. Descriptor table is a shared resource; two fget() on the same descriptor may return different struct file references. get_tap_ptr_ring() is called after we'd found (and pinned) the socket we'll be using and it tries to find the private tun/tap data structures associated with it. Redoing the lookup by the same file descriptor we'd used to get the socket is racy - we need to same struct file. Thanks to Jason for spotting a braino in the original variant of patch - I'd missed the use of fd == -1 for disabling backend, and in that case we can end up with sock == NULL and sock != oldsock. Cc: stable@kernel.org Acked-by: Michael S. Tsirkin Signed-off-by: Jason Wang Signed-off-by: Al Viro Signed-off-by: Greg Kroah-Hartman

tuntap: add sanity checks about msg_controllen in sendmsg

2022-04-13T19:00:59+00:00

[ Upstream commit 74a335a07a17d131b9263bfdbdcb5e40673ca9ca ] In patch [1], tun_msg_ctl was added to allow pass batched xdp buffers to tun_sendmsg. Although we donot use msg_controllen in this path, we should check msg_controllen to make sure the caller pass a valid msg_ctl. [1]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=fe8dd45bb7556246c6b76277b1ba4296c91c2505 Reported-by: Eric Dumazet Suggested-by: Jason Wang Signed-off-by: Harold Huang Acked-by: Jason Wang Link: https://lore.kernel.org/r/20220303022441.383865-1-baymaxhuang@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

vhost_net: fix OoB on sendmsg() failure.

2021-09-22T10:27:58+00:00

commit 3c4cea8fa7f71f00c5279547043a84bc2a4d8b8c upstream. If the sendmsg() call in vhost_tx_batch() fails, both the 'batched_xdp' and 'done_idx' indexes are left unchanged. If such failure happens when batched_xdp == VHOST_NET_BATCH, the next call to vhost_net_build_xdp() will access and write memory outside the xdp buffers area. Since sendmsg() can only error with EBADFD, this change addresses the issue explicitly freeing the XDP buffers batch on error. Fixes: 0a0be13b8fe2 ("vhost_net: batch submitting XDP buffers to underlayer sockets") Suggested-by: Jason Wang Signed-off-by: Paolo Abeni Acked-by: Jason Wang Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

vhost_net: fix ubuf refcount incorrectly when sendmsg fails

2021-01-12T19:18:13+00:00

[ Upstream commit 01e31bea7e622f1890c274f4aaaaf8bccd296aa5 ] Currently the vhost_zerocopy_callback() maybe be called to decrease the refcount when sendmsg fails in tun. The error handling in vhost handle_tx_zerocopy() will try to decrease the same refcount again. This is wrong. To fix this issue, we only call vhost_net_ubuf_put() when vq->heads[nvq->desc].len == VHOST_DMA_IN_PROGRESS. Fixes: bab632d69ee4 ("vhost: vhost TX zero-copy support") Signed-off-by: Yunjian Wang Acked-by: Willem de Bruijn Acked-by: Michael S. Tsirkin Acked-by: Jason Wang Link: https://lore.kernel.org/r/1609207308-20544-1-git-send-email-wangyunjian@huawei.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost

2020-08-11T21:34:17+00:00

Pull virtio updates from Michael Tsirkin: - IRQ bypass support for vdpa and IFC - MLX5 vdpa driver - Endianness fixes for virtio drivers - Misc other fixes * tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost: (71 commits) vdpa/mlx5: fix up endian-ness for mtu vdpa: Fix pointer math bug in vdpasim_get_config() vdpa/mlx5: Fix pointer math in mlx5_vdpa_get_config() vdpa/mlx5: fix memory allocation failure checks vdpa/mlx5: Fix uninitialised variable in core/mr.c vdpa_sim: init iommu lock virtio_config: fix up warnings on parisc vdpa/mlx5: Add VDPA driver for supported mlx5 devices vdpa/mlx5: Add shared memory registration code vdpa/mlx5: Add support library for mlx5 VDPA implementation vdpa/mlx5: Add hardware descriptive header file vdpa: Modify get_vq_state() to return error code net/vdpa: Use struct for set/get vq state vdpa: remove hard coded virtq num vdpasim: support batch updating vhost-vdpa: support IOTLB batching hints vhost-vdpa: support get/set backend features vhost: generialize backend features setting/getting vhost-vdpa: refine ioctl pre-processing vDPA: dont change vq irq after DRIVER_OK ...

vhost: generialize backend features setting/getting

2020-08-05T22:39:18+00:00

Move the backend features setting/getting from net.c to vhost.c to be reused by vhost-vdpa. Signed-off-by: Jason Wang Link: https://lore.kernel.org/r/20200804162048.22587-3-eli@mellanox.com Signed-off-by: Michael S. Tsirkin

virtio: VIRTIO_F_IOMMU_PLATFORM -> VIRTIO_F_ACCESS_PLATFORM

2020-08-03T20:11:42+00:00

Rename the bit to match latest virtio spec. Add a compat macro to avoid breaking existing userspace. Signed-off-by: Michael S. Tsirkin Reviewed-by: David Hildenbrand