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authorLongpeng(Mike) <longpeng2@huawei.com>2021-08-12 08:30:56 +0300
committerJakub Kicinski <kuba@kernel.org>2021-08-12 20:57:27 +0300
commit49b0b6ffe20c5344f4173f3436298782a08da4f2 (patch)
tree987cce64fc41f2ce4609895a61d95d313ca3a6bd /net/vmw_vsock
parentd9d5b8961284b0051726e0fcda91d1e297e087f5 (diff)
downloadlinux-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>
Diffstat (limited to 'net/vmw_vsock')
-rw-r--r--net/vmw_vsock/virtio_transport.c7
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)