vsock: avoid timeout during connect() if the socket is closing
[ Upstream commit fccd2b711d9628c7ce0111d5e4938652101ee30a ] When a peer attempts to establish a connection, vsock_connect() contains a loop that waits for the state to be TCP_ESTABLISHED. However, the other peer can be fast enough to accept the connection and close it immediately, thus moving the state to TCP_CLOSING. When this happens, the peer in the vsock_connect() is properly woken up, but since the state is not TCP_ESTABLISHED, it goes back to sleep until the timeout expires, returning -ETIMEDOUT. If the socket state is TCP_CLOSING, waiting for the timeout is pointless. vsock_connect() can return immediately without errors or delay since the connection actually happened. The socket will be in a closing state, but this is not an issue, and subsequent calls will fail as expected. We discovered this issue while developing a test that accepts and immediately closes connections to stress the transport switch between two connect() calls, where the first one was interrupted by a signal (see Closes link). Reported-by:Luigi Leonardi <leonardi@redhat.com> Closes: https://lore.kernel.org/virtualization/bq6hxrolno2vmtqwcvb5bljfpb7mvwb3kohrvaed6auz5vxrfv@ijmd2f3grobn/ Fixes: d021c344 ("VSOCK: Introduce VM Sockets") Signed-off-by:
Stefano Garzarella <sgarzare@redhat.com> Acked-by:
Paolo Abeni <pabeni@redhat.com> Tested-by:
Luigi Leonardi <leonardi@redhat.com> Reviewed-by:
Luigi Leonardi <leonardi@redhat.com> Link: https://patch.msgid.link/20250328141528.420719-1-sgarzare@redhat.com Signed-off-by:
Jakub Kicinski <kuba@kernel.org> Signed-off-by:
Sasha Levin <sashal@kernel.org>
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