From: Gerhard Engleder gerhard@engleder-embedded.com
[ Upstream commit 05ee658c654bacda03f7fecef367e62aaf8e1cfe ]
BPF map iteration in xdp1_user results in endless loop without any output, because the return value of bpf_map_get_next_key() is checked against the wrong value.
Other call locations of bpf_map_get_next_key() check for equal 0 for continuing the iteration. xdp1_user checks against unequal -1. This is wrong for a function which can return arbitrary negative errno values, because a return value of e.g. -2 results in an endless loop.
With this fix xdp1_user is printing statistics again: proto 0: 1 pkt/s proto 0: 1 pkt/s proto 17: 107383 pkt/s proto 17: 881655 pkt/s proto 17: 882083 pkt/s proto 17: 881758 pkt/s
Fixes: bd054102a8c7 ("libbpf: enforce strict libbpf 1.0 behaviors") Signed-off-by: Gerhard Engleder gerhard@engleder-embedded.com Acked-by: Song Liu song@kernel.org Link: https://lore.kernel.org/r/20221013200922.17167-1-gerhard@engleder-embedded.c... Signed-off-by: Martin KaFai Lau martin.lau@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- samples/bpf/xdp1_user.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/samples/bpf/xdp1_user.c b/samples/bpf/xdp1_user.c index ac370e638fa3..281dc964de8d 100644 --- a/samples/bpf/xdp1_user.c +++ b/samples/bpf/xdp1_user.c @@ -51,7 +51,7 @@ static void poll_stats(int map_fd, int interval)
sleep(interval);
- while (bpf_map_get_next_key(map_fd, &key, &key) != -1) { + while (bpf_map_get_next_key(map_fd, &key, &key) == 0) { __u64 sum = 0;
assert(bpf_map_lookup_elem(map_fd, &key, values) == 0);