Thanks, I'll fix the `shutdown()` error path to `goto close_epoll` in v4.
On Wed, Apr 22, 2026 at 6:59 AM Kuniyuki Iwashima <[email protected]> wrote:
>
> On Tue, Apr 21, 2026 at 5:31 AM Zhenzhong Wu <[email protected]> wrote:
> >
> > Inside migrate_dance(), add epoll checks around shutdown() to
> > verify that the target listener is not ready before shutdown()
> > and becomes ready immediately after shutdown() triggers migration.
> >
> > Cover TCP_ESTABLISHED and TCP_SYN_RECV. Exclude TCP_NEW_SYN_RECV
> > as it depends on later handshake completion.
> >
> > Suggested-by: Kuniyuki Iwashima <[email protected]>
> > Signed-off-by: Zhenzhong Wu <[email protected]>
> > ---
> > .../bpf/prog_tests/migrate_reuseport.c | 46 ++++++++++++++++---
> > 1 file changed, 40 insertions(+), 6 deletions(-)
> >
> > diff --git a/tools/testing/selftests/bpf/prog_tests/migrate_reuseport.c
> > b/tools/testing/selftests/bpf/prog_tests/migrate_reuseport.c
> > index 653b0a20f..6180a79a7 100644
> > --- a/tools/testing/selftests/bpf/prog_tests/migrate_reuseport.c
> > +++ b/tools/testing/selftests/bpf/prog_tests/migrate_reuseport.c
> > @@ -7,24 +7,29 @@
> > * 3. call listen() for 1 server socket. (migration target)
> > * 4. update a map to migrate all child sockets
> > * to the last server socket (migrate_map[cookie] = 4)
> > - * 5. call shutdown() for first 4 server sockets
> > + * 5. for TCP_ESTABLISHED and TCP_SYN_RECV cases, verify via epoll
> > + * that the last server socket is not ready before migration.
> > + * 6. call shutdown() for first 4 server sockets
> > * and migrate the requests in the accept queue
> > * to the last server socket.
> > - * 6. call listen() for the second server socket.
> > - * 7. call shutdown() for the last server
> > + * 7. for TCP_ESTABLISHED and TCP_SYN_RECV cases, verify via epoll
> > + * that the last server socket is ready after migration.
> > + * 8. call listen() for the second server socket.
> > + * 9. call shutdown() for the last server
> > * and migrate the requests in the accept queue
> > * to the second server socket.
> > - * 8. call listen() for the last server.
> > - * 9. call shutdown() for the second server
> > + * 10. call listen() for the last server.
> > + * 11. call shutdown() for the second server
> > * and migrate the requests in the accept queue
> > * to the last server socket.
> > - * 10. call accept() for the last server socket.
> > + * 12. call accept() for the last server socket.
> > *
> > * Author: Kuniyuki Iwashima <[email protected]>
> > */
> >
> > #include <bpf/bpf.h>
> > #include <bpf/libbpf.h>
> > +#include <sys/epoll.h>
> >
> > #include "test_progs.h"
> > #include "test_migrate_reuseport.skel.h"
> > @@ -350,8 +355,28 @@ static int update_maps(struct
> > migrate_reuseport_test_case *test_case,
> >
> > static int migrate_dance(struct migrate_reuseport_test_case *test_case)
> > {
> > + struct epoll_event ev = {
> > + .events = EPOLLIN,
> > + };
> > + int epoll = -1, nfds;
> > int i, err;
> >
> > + if (test_case->state != BPF_TCP_NEW_SYN_RECV) {
> > + epoll = epoll_create1(0);
> > + if (!ASSERT_NEQ(epoll, -1, "epoll_create1"))
> > + return -1;
> > +
> > + ev.data.fd = test_case->servers[MIGRATED_TO];
> > + if (!ASSERT_OK(epoll_ctl(epoll, EPOLL_CTL_ADD,
> > + test_case->servers[MIGRATED_TO],
> > &ev),
> > + "epoll_ctl"))
> > + goto close_epoll;
> > +
> > + nfds = epoll_wait(epoll, &ev, 1, 0);
> > + if (!ASSERT_EQ(nfds, 0, "epoll_wait 1"))
> > + goto close_epoll;
> > + }
> > +
> > /* Migrate TCP_ESTABLISHED and TCP_SYN_RECV requests
> > * to the last listener based on eBPF.
> > */
>
> Sorry I forgot to update return -1 to goto close_epoll
> when shutdown() fails.
>
> Otherwise looks good.
>
> Reviewed-by: Kuniyuki Iwashima <[email protected]>
>
>
> > @@ -365,6 +390,15 @@ static int migrate_dance(struct
> > migrate_reuseport_test_case *test_case)
> > if (test_case->state == BPF_TCP_NEW_SYN_RECV)
> > return 0;
> >
> > + nfds = epoll_wait(epoll, &ev, 1, 0);
> > + if (!ASSERT_EQ(nfds, 1, "epoll_wait 2")) {
> > +close_epoll:
> > + close(epoll);
> > + return -1;
> > + }
> > +
> > + close(epoll);
> > +
> > /* Note that we use the second listener instead of the
> > * first one here.
> > *
> > --
> > 2.43.0
> >
