When xsend() returns -1 (error), the check 'n < sizeof(buf)' incorrectly treats it as success due to unsigned promotion. Explicitly check for -1 first.

Fixes: a4b7193d8efd ("selftests/bpf: Add sockmap test for redirecting partial skb data") Signed-off-by: Fushuai Wang wangfushuai@baidu.com --- tools/testing/selftests/bpf/prog_tests/sockmap_listen.c | 2 ++ 1 file changed, 2 insertions(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_listen.c b/tools/testing/selftests/bpf/prog_tests/sockmap_listen.c index 1d98eee7a2c3..f1bdccc7e4e7 100644 --- a/tools/testing/selftests/bpf/prog_tests/sockmap_listen.c +++ b/tools/testing/selftests/bpf/prog_tests/sockmap_listen.c @@ -924,6 +924,8 @@ static void redir_partial(int family, int sotype, int sock_map, int parser_map) goto close;

n = xsend(c1, buf, sizeof(buf), 0); + if (n == -1) + goto close; if (n < sizeof(buf)) FAIL("incomplete write");