From: Magnus Karlsson <magnus.karlsson@intel.com>

Date: Thu, 10 Dec 2020 17:34:07 +0100

Subject: samples/bpf: Fix possible hang in xdpsock with multiple threads

Patch-mainline: v5.11-rc1

Git-commit: 092fde0f863b72b67c4d6dc03844f5658fc00a35

References: bsc#1155518

Fix a possible hang in xdpsock that can occur when using multiple

threads. In this case, one or more of the threads might get stuck in

the while-loop in tx_only after the user has signaled the main thread

to stop execution. In this case, no more Tx packets will be sent, so a

thread might get stuck in the aforementioned while-loop. Fix this by

introducing a test inside the while-loop to check if the benchmark has

been terminated. If so, return from the function.

Fixes: cd9e72b6f210 ("samples/bpf: xdpsock: Add option to specify batch size")

Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Link: https://lore.kernel.org/bpf/20201210163407.22066-1-magnus.karlsson@gmail.com

Acked-by: Gary Lin <glin@suse.com>

---

 samples/bpf/xdpsock_user.c |    2 ++

 1 file changed, 2 insertions(+)

--- a/samples/bpf/xdpsock_user.c

+++ b/samples/bpf/xdpsock_user.c

@@ -929,6 +929,8 @@ static void tx_only(struct xsk_socket_in

 	while (xsk_ring_prod__reserve(&xsk->tx, batch_size, &idx) <

 				      batch_size) {

 		complete_tx_only(xsk, batch_size);

+		if (benchmark_done)

+			return;

 	}

 	for (i = 0; i < batch_size; i++) {