[PATCH 5.12 018/178] libbpf: Fixes incorrect rx_ring_setup_done

Greg Kroah-Hartman
2021-06-21T16:37:50Z

From: Kev Jackson <foamdino@gmail.com>

[ Upstream commit 11fc79fc9f2e395aa39fa5baccae62767c5d8280 ]

When calling xsk_socket__create_shared(), the logic at line 1097 marks a
boolean flag true within the xsk_umem structure to track setup progress
in order to support multiple calls to the function. However, instead of
marking umem->tx_ring_setup_done, the code incorrectly sets
umem->rx_ring_setup_done. This leads to improper behaviour when
creating and destroying xsk and umem structures.

Multiple calls to this function is documented as supported.

Fixes: ca7a83e2487a ("libbpf: Only create rx and tx XDP rings when necessary")
Signed-off-by: Kev Jackson <foamdino@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/YL4aU4f3Aaik7CN0@linux-dev
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
tools/lib/bpf/xsk.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c
index 007fe5d59438..fe2bec500bf6 100644
--- a/tools/lib/bpf/xsk.c
+++ b/tools/lib/bpf/xsk.c
@@ -928,7 +928,7 @@ int xsk_socket__create_shared(struct xsk_socket **xsk_ptr,
goto out_put_ctx;
}
if (xsk->fd == umem->fd)
- umem->rx_ring_setup_done = true;
+ umem->tx_ring_setup_done = true;
}

err = xsk_get_mmap_offsets(xsk->fd, &off);
--
2.30.2