[PATCH v6 0/3] vsock: fix stale sk_err handling after a failed connect

A socket whose connect() failed keeps sk_err set. If that socket is
later reused as a listener, vsock_accept() rejects an unrelated
incoming connection, and on virtio/hyperv the resulting child socket
is leaked.

Patch 1 removes the listener's sk_err check from vsock_accept(), since
no vsock transport ever sets sk_err on a TCP_LISTEN socket. This will
fix what the syzbot reported.

Patch 2 removes vsock_sock.rejected, now unreachable after patch 1.

Patch 3 is a related but separate fix: vsock_connect() now consumes
sk_err via sock_error() once it has been returned to userspace, so a
failed blocking connect() doesn't keep reporting the same error a
second time.

---
Changes in v6:
- Reorder if/else in vsock_accept() to put the smaller block first.
- Add historical context to patch 2
v5: https://lore.kernel.org/netdev/[email protected]/
- Split into a series
- Remove the now-unused rejected flag from vsock_sock
v4: https://lore.kernel.org/netdev/[email protected]/
- Remove sk_err checks from vsock_accept()
v3: https://lore.kernel.org/netdev/[email protected]/
- Fix truncated title and add annotations to reproducer steps.
v2: https://lore.kernel.org/netdev/[email protected]/
- Add reproducer steps to commit message.
v1: https://lore.kernel.org/netdev/[email protected]/

Nguyen Dinh Phi (3):
  vsock: don't check the listener's sk_err in vsock_accept()
  vsock: remove the now-unused rejected flag
  vsock: use sock_error() to consume sk_err after a failed connect

 include/net/af_vsock.h   |  5 +---
 net/vmw_vsock/af_vsock.c | 62 +++++++++++++---------------------------
 2 files changed, 21 insertions(+), 46 deletions(-)

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2.53.0