diff options
| author | Petar Penkov <ppenkov@google.com> | 2019-08-16 10:08:25 -0700 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2019-08-17 23:16:25 +0200 |
| commit | fae55527ac1164b66bee983a4d82ade2bfedb332 (patch) | |
| tree | b0939375f0abb2c3e2b5688763cea97962316bdc | |
| parent | 929ffa6e9df0832fdf541ff2d9532e209153c0ec (diff) | |
| download | linux-fae55527ac1164b66bee983a4d82ade2bfedb332.tar.bz2 | |
selftests/bpf: fix race in test_tcp_rtt test
There is a race in this test between receiving the ACK for the
single-byte packet sent in the test, and reading the values from the
map.
This patch fixes this by having the client wait until there are no more
unacknowledged packets.
Before:
for i in {1..1000}; do ../net/in_netns.sh ./test_tcp_rtt; \
done | grep -c PASSED
< trimmed error messages >
993
After:
for i in {1..10000}; do ../net/in_netns.sh ./test_tcp_rtt; \
done | grep -c PASSED
10000
Fixes: b55873984dab ("selftests/bpf: test BPF_SOCK_OPS_RTT_CB")
Signed-off-by: Petar Penkov <ppenkov@google.com>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
| -rw-r--r-- | tools/testing/selftests/bpf/test_tcp_rtt.c | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/test_tcp_rtt.c b/tools/testing/selftests/bpf/test_tcp_rtt.c index 90c3862f74a8..93916a69823e 100644 --- a/tools/testing/selftests/bpf/test_tcp_rtt.c +++ b/tools/testing/selftests/bpf/test_tcp_rtt.c @@ -6,6 +6,7 @@ #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> +#include <netinet/tcp.h> #include <pthread.h> #include <linux/filter.h> @@ -34,6 +35,30 @@ static void send_byte(int fd) error(1, errno, "Failed to send single byte"); } +static int wait_for_ack(int fd, int retries) +{ + struct tcp_info info; + socklen_t optlen; + int i, err; + + for (i = 0; i < retries; i++) { + optlen = sizeof(info); + err = getsockopt(fd, SOL_TCP, TCP_INFO, &info, &optlen); + if (err < 0) { + log_err("Failed to lookup TCP stats"); + return err; + } + + if (info.tcpi_unacked == 0) + return 0; + + usleep(10); + } + + log_err("Did not receive ACK"); + return -1; +} + static int verify_sk(int map_fd, int client_fd, const char *msg, __u32 invoked, __u32 dsack_dups, __u32 delivered, __u32 delivered_ce, __u32 icsk_retransmits) @@ -149,6 +174,11 @@ static int run_test(int cgroup_fd, int server_fd) /*icsk_retransmits=*/0); send_byte(client_fd); + if (wait_for_ack(client_fd, 100) < 0) { + err = -1; + goto close_client_fd; + } + err += verify_sk(map_fd, client_fd, "first payload byte", /*invoked=*/2, @@ -157,6 +187,7 @@ static int run_test(int cgroup_fd, int server_fd) /*delivered_ce=*/0, /*icsk_retransmits=*/0); +close_client_fd: close(client_fd); close_bpf_object: |