From: Dmitry Safonov <0x7f454c46@xxxxxxxxx> It turns to be that open_netns() is called rarely from the child-thread and more often from parent-thread. Yet, on initialization of kconfig checks, either of threads may reach kconfig_lock mutex first. VRF-related checks do create a temporary ksft-check VRF in an unshare()'d namespace and than setns() back to the original. As original was opened from "/proc/self/ns/net", it's valid for thread-leader (parent), but it's invalid for the child, resulting in the following failure on tests that check has_vrfs() support: > # ok 54 TCP-AO required on socket + TCP-MD5 key: prefailed as expected: Key was rejected by service > # not ok 55 # error 381[unsigned-md5.c:24] Failed to add a VRF: -17 > # not ok 56 # error 383[unsigned-md5.c:33] Failed to add a route to VRF: -22: Key was rejected by service > not ok 1 selftests: net/tcp_ao: unsigned-md5_ipv6 # exit=1 Use "/proc/thread-self/ns/net" which is valid for any thread. Signed-off-by: Dmitry Safonov <0x7f454c46@xxxxxxxxx> --- tools/testing/selftests/net/tcp_ao/lib/setup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/net/tcp_ao/lib/setup.c b/tools/testing/selftests/net/tcp_ao/lib/setup.c index e408b9243b2c..d5212ffe9489 100644 --- a/tools/testing/selftests/net/tcp_ao/lib/setup.c +++ b/tools/testing/selftests/net/tcp_ao/lib/setup.c @@ -111,7 +111,7 @@ static void sig_int(int signo) int open_netns(void) { - const char *netns_path = "/proc/self/ns/net"; + const char *netns_path = "/proc/thread-self/ns/net"; int fd; fd = open(netns_path, O_RDONLY); -- 2.42.2