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| author | Longpeng(Mike) <longpeng2@huawei.com> | 2021-08-12 08:30:56 +0300 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2021-08-12 20:57:27 +0300 |
| commit | 49b0b6ffe20c5344f4173f3436298782a08da4f2 (patch) | |
| tree | 987cce64fc41f2ce4609895a61d95d313ca3a6bd | |
| parent | d9d5b8961284b0051726e0fcda91d1e297e087f5 (diff) | |
| download | linux-49b0b6ffe20c5344f4173f3436298782a08da4f2.tar.xz | |
vsock/virtio: avoid potential deadlock when vsock device remove
There's a potential deadlock case when remove the vsock device or
process the RESET event:
vsock_for_each_connected_socket:
spin_lock_bh(&vsock_table_lock) ----------- (1)
...
virtio_vsock_reset_sock:
lock_sock(sk) --------------------- (2)
...
spin_unlock_bh(&vsock_table_lock)
lock_sock() may do initiative schedule when the 'sk' is owned by
other thread at the same time, we would receivce a warning message
that "scheduling while atomic".
Even worse, if the next task (selected by the scheduler) try to
release a 'sk', it need to request vsock_table_lock and the deadlock
occur, cause the system into softlockup state.
Call trace:
queued_spin_lock_slowpath
vsock_remove_bound
vsock_remove_sock
virtio_transport_release
__vsock_release
vsock_release
__sock_release
sock_close
__fput
____fput
So we should not require sk_lock in this case, just like the behavior
in vhost_vsock or vmci.
Fixes: 0ea9e1d3a9e3 ("VSOCK: Introduce virtio_transport.ko")
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Longpeng(Mike) <longpeng2@huawei.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Link: https://lore.kernel.org/r/20210812053056.1699-1-longpeng2@huawei.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | net/vmw_vsock/virtio_transport.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c index e0c2c992ad9c..4f7c99dfd16c 100644 --- a/net/vmw_vsock/virtio_transport.c +++ b/net/vmw_vsock/virtio_transport.c @@ -357,11 +357,14 @@ static void virtio_vsock_event_fill(struct virtio_vsock *vsock) static void virtio_vsock_reset_sock(struct sock *sk) { - lock_sock(sk); + /* vmci_transport.c doesn't take sk_lock here either. At least we're + * under vsock_table_lock so the sock cannot disappear while we're + * executing. + */ + sk->sk_state = TCP_CLOSE; sk->sk_err = ECONNRESET; sk_error_report(sk); - release_sock(sk); } static void virtio_vsock_update_guest_cid(struct virtio_vsock *vsock) |