[net-next,v4,4/8] selftests/net: Open /proc/thread-self in open_netns()

Commit Message

Dmitry Safonov via B4 Relay Aug. 23, 2024, 10:04 p.m. UTC

From: Dmitry Safonov <[e-mail]>

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 <[e-mail]>
---
 tools/testing/selftests/net/tcp_ao/lib/setup.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Patch

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);