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728836ebca
virtio_vsock_remove() stops the virtqueues and then flushes each work
item before freeing the enclosing virtio_vsock. The current order does
not account for dependencies between those items: tx_work may queue
send_pkt_work, and send_pkt_work may queue rx_work.
In particular, send_pkt_work can set restart_rx and release tx_lock.
The remove path can then stop the queues and flush rx_work before
send_pkt_work queues it. Although the later send_pkt_work flush waits
for that producer to finish, nothing waits for the newly queued rx_work,
so kfree(vsock) can race with it.
KASAN reported:
BUG: KASAN: slab-use-after-free in
virtio_transport_rx_work+0x487/0x4b0
Read of size 8 at addr ffff888114c2b008 by task kworker/1:1/47
Workqueue: virtio_vsock virtio_transport_rx_work
Call Trace:
virtio_transport_rx_work+0x487/0x4b0
process_one_work+0x688/0x1120
worker_thread+0x45b/0xd10
Allocated by task 1:
virtio_vsock_probe+0xef/0x6b0
Freed by task 84:
kfree+0x131/0x3c0
virtio_vsock_remove+0xd1/0x100
Flush the works in producer-to-consumer order. virtio_vsock_vqs_del()
has already disabled the queue callbacks and cleared the run flags, so
after tx_work and send_pkt_work are drained, no source remains that can
queue rx_work after its flush.
Fixes: 0ea9e1d3a9 ("VSOCK: Introduce virtio_transport.ko")
Cc: stable@vger.kernel.org
Signed-off-by: Chengfeng Ye <nicoyip.dev@gmail.com>
Link: https://patch.msgid.link/20260822164556.3750959-1-nicoyip.dev@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>