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bfd1ce30e1
The virtio vsock driver has a small window during initialization where it can silently drop replies to connection requests. Because no reply is sent, kata waits for 10 seconds and in the end it generates a connection timeout error in HybridVSockDialer. Fixes: #8291 Signed-off-by: Alexandru Matei <alexandru.matei@uipath.com>
74 lines
2.3 KiB
Diff
74 lines
2.3 KiB
Diff
From d03fb89b5e6dcaf399480708ee2d5a32dca70e7a Mon Sep 17 00:00:00 2001
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From: "Longpeng(Mike)" <longpeng2@huawei.com>
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Date: Thu, 12 Aug 2021 13:30:56 +0800
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Subject: [PATCH 1/7] vsock/virtio: avoid potential deadlock when vsock device
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remove
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There's a potential deadlock case when remove the vsock device or
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process the RESET event:
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vsock_for_each_connected_socket:
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spin_lock_bh(&vsock_table_lock) ----------- (1)
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...
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virtio_vsock_reset_sock:
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lock_sock(sk) --------------------- (2)
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...
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spin_unlock_bh(&vsock_table_lock)
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lock_sock() may do initiative schedule when the 'sk' is owned by
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other thread at the same time, we would receivce a warning message
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that "scheduling while atomic".
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Even worse, if the next task (selected by the scheduler) try to
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release a 'sk', it need to request vsock_table_lock and the deadlock
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occur, cause the system into softlockup state.
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Call trace:
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queued_spin_lock_slowpath
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vsock_remove_bound
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vsock_remove_sock
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virtio_transport_release
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__vsock_release
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vsock_release
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__sock_release
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sock_close
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__fput
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____fput
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So we should not require sk_lock in this case, just like the behavior
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in vhost_vsock or vmci.
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Fixes: 0ea9e1d3a9e3 ("VSOCK: Introduce virtio_transport.ko")
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Cc: Stefan Hajnoczi <stefanha@redhat.com>
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Signed-off-by: Longpeng(Mike) <longpeng2@huawei.com>
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Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
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Link: https://lore.kernel.org/r/20210812053056.1699-1-longpeng2@huawei.com
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Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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---
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net/vmw_vsock/virtio_transport.c | 7 +++++--
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1 file changed, 5 insertions(+), 2 deletions(-)
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diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
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index 2700a63ab095..3a056f8affd1 100644
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--- a/net/vmw_vsock/virtio_transport.c
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+++ b/net/vmw_vsock/virtio_transport.c
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@@ -356,11 +356,14 @@ static void virtio_vsock_event_fill(struct virtio_vsock *vsock)
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static void virtio_vsock_reset_sock(struct sock *sk)
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{
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- lock_sock(sk);
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+ /* vmci_transport.c doesn't take sk_lock here either. At least we're
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+ * under vsock_table_lock so the sock cannot disappear while we're
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+ * executing.
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+ */
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+
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sk->sk_state = TCP_CLOSE;
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sk->sk_err = ECONNRESET;
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sk->sk_error_report(sk);
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- release_sock(sk);
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}
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static void virtio_vsock_update_guest_cid(struct virtio_vsock *vsock)
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--
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2.34.1
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