In smc_connect_work(), when the underlying TCP handshake fails, the error
code (rc) must be propagated to sk_err to ensure userspace can correctly
retrieve the error status via SO_ERROR. Currently, the code only handles
a restricted set of error codes (e.g., EPIPE, ECONNREFUSED). If other
errors occurs, such as EHOSTUNREACH, sk_err remains unset (zero).
This affects applications that rely on SO_ERROR to determine connect
outcome. For example, higher versions of Go's netpoller treats
SO_ERROR == 0 combined with a failed getpeername() as a spurious wakeup
and re-enters epoll_wait(). Under ET mode, no further edge will be
generated since the socket is already in a terminal state, causing the
connect to hang indefinitely or until a user-specified timeout, if one
is set.
Fixes: 50717a37db ("net/smc: nonblocking connect rework")
Signed-off-by: D. Wythe <alibuda@linux.alibaba.com>
Reviewed-by: Dust Li <dust.li@linux.alibaba.com>
Link: https://patch.msgid.link/20260506014105.27093-1-alibuda@linux.alibaba.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
9032f76769