On Wed, Jul 29, 2026 at 12:16:55PM -0700, Weiming Shi wrote:
> Commit b917507e5ad9 ("vsock/virtio: stop workers during the .remove()")
> made the RX worker jump to its common exit when rx_run is clear. That
> exit still refills the RX queue when the buffer count is low, so work
> queued across virtio_vsock_vqs_del() can add buffers after the virtqueues
> have been deleted.
>
> BUG: KASAN: slab-use-after-free in virtqueue_add_sgs
> Read of size 4 by task kworker/0:1
> Workqueue: virtio_vsock virtio_transport_rx_work
> Call Trace:
> virtqueue_add_sgs (drivers/virtio/virtio_ring.c:2796)
> virtio_vsock_rx_fill (net/vmw_vsock/virtio_transport.c:332)
> virtio_transport_rx_work (net/vmw_vsock/virtio_transport.c:701)
> process_one_work (kernel/workqueue.c:3314)
> worker_thread (kernel/workqueue.c:3478)
> kthread (kernel/kthread.c:436)
> ret_from_fork (arch/x86/kernel/process.c:158)
> ret_from_fork_asm (arch/x86/entry/entry_64.S:245)
> ...
> Freed by task 141:
> kfree (mm/slub.c:6566)
> vp_del_vq (drivers/virtio/virtio_pci_common.c:259)
> vp_del_vqs (drivers/virtio/virtio_pci_common.c:285)
> virtio_vsock_freeze (net/vmw_vsock/virtio_transport.c:912)
> virtio_device_freeze (drivers/virtio/virtio.c:658)
> virtio_pci_freeze (drivers/virtio/virtio_pci_common.c:601)
> pci_pm_freeze (drivers/pci/pci-driver.c:1098)
> device_suspend (drivers/base/power/main.c:1968)
> Kernel panic - not syncing: KASAN: panic_on_warn set ...
>
> Jump to a no-refill exit when rx_run is clear, leaving the normal exit
> to replenish a running queue.
>
> Fixes: b917507e5ad9 ("vsock/virtio: stop workers during the .remove()")
> Cc: [email protected]
> Reported-by: Xiang Mei <[email protected]>
> Link: https://lore.kernel.org/r/[email protected]
> Suggested-by: Stefano Garzarella <[email protected]>
> Assisted-by: OpenAI-Codex:gpt-5
> Signed-off-by: Weiming Shi <[email protected]>
> ---
> net/vmw_vsock/virtio_transport.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/net/vmw_vsock/virtio_transport.c
> b/net/vmw_vsock/virtio_transport.c
> index a8e1dd95ba8c..96c9fe8d357c 100644
> --- a/net/vmw_vsock/virtio_transport.c
> +++ b/net/vmw_vsock/virtio_transport.c
> @@ -638,7 +638,7 @@ static void virtio_transport_rx_work(struct work_struct
> *work)
> mutex_lock(&vsock->rx_lock);
>
> if (!vsock->rx_run)
> - goto out;
> + goto out_nofill;
>
> vq = vsock->vqs[VSOCK_VQ_RX];
>
> @@ -692,6 +692,7 @@ static void virtio_transport_rx_work(struct work_struct
> *work)
> out:
> if (vsock->rx_buf_nr < vsock->rx_buf_max_nr / 2)
> virtio_vsock_rx_fill(vsock);
> +out_nofill:
> mutex_unlock(&vsock->rx_lock);
> }
>
> --
> 2.55.0
>
Reviewed-by: Bobby Eshleman <[email protected]>
