diff mbox series

[bpf-next,2/3] samples/bpf: fix possible deadlock in xdpsock

Message ID 1599726666-8431-3-git-send-email-magnus.karlsson@gmail.com
State New
Headers show
Series None | expand

Commit Message

Magnus Karlsson Sept. 10, 2020, 8:31 a.m. UTC 
From: Magnus Karlsson <magnus.karlsson@intel.com>

Fix a possible deadlock in the l2fwd application in xdpsock that can
occur when there is no space in the Tx ring. There are two ways to get
the kernel to consume entries in the Tx ring: calling sendto() to make
it send packets and freeing entries from the completion ring, as the
kernel will not send a packet if there is no space for it to add a
completion entry in the completion ring. The Tx loop in l2fwd only
used to call sendto(). This patches adds cleaning the completion ring
in that loop.

Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
---
 samples/bpf/xdpsock_user.c | 1 +
 1 file changed, 1 insertion(+)
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Patch

diff --git a/samples/bpf/xdpsock_user.c b/samples/bpf/xdpsock_user.c
index b6175cb..b60bf4e 100644
--- a/samples/bpf/xdpsock_user.c
+++ b/samples/bpf/xdpsock_user.c
@@ -1125,6 +1125,7 @@  static void l2fwd(struct xsk_socket_info *xsk, struct pollfd *fds)
 	while (ret != rcvd) {
 		if (ret < 0)
 			exit_with_error(-ret);
+		complete_tx_l2fwd(xsk, fds);
 		if (xsk_ring_prod__needs_wakeup(&xsk->tx))
 			kick_tx(xsk);
 		ret = xsk_ring_prod__reserve(&xsk->tx, rcvd, &idx_tx);