From fdb48976b6379c2b91e1ad4aafef07ee8b1ddb0e Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ricardo=20B=2E=20Marli=C3=A8re?= Date: Tue, 7 Apr 2026 11:35:45 -0300 Subject: [PATCH 1/3] selftests/namespaces: Kill grandchild in nsid fixture teardown MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The timens_separate and pidns_separate test cases fork a grandchild that calls pause(). FIXTURE_TEARDOWN only kills the direct child, which is the init process of the grandchild's namespace. Once the child (init) exits, the grandchild is reparented to the host init but remains alive and continues to hold the inherited write end of the test runner's TAP pipe open. tap_prefix never receives EOF and blocks indefinitely, hanging the entire test collection. Record the grandchild PID in the fixture struct so that teardown can send SIGKILL and reap it before dealing with the child. The grandchild must be reaped first because the child acts as its PID namespace init; killing the child first would kill the grandchild without giving us a chance to waitpid() it. Signed-off-by: Ricardo B. Marlière Link: https://patch.msgid.link/20260407-selftests-namespaces_fixes-v1-1-59109909d88b@suse.com Signed-off-by: Christian Brauner --- tools/testing/selftests/namespaces/nsid_test.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/namespaces/nsid_test.c b/tools/testing/selftests/namespaces/nsid_test.c index b4a14c6693a5..46dc838cba82 100644 --- a/tools/testing/selftests/namespaces/nsid_test.c +++ b/tools/testing/selftests/namespaces/nsid_test.c @@ -25,14 +25,24 @@ /* Fixture for tests that create child processes */ FIXTURE(nsid) { pid_t child_pid; + pid_t grandchild_pid; }; FIXTURE_SETUP(nsid) { self->child_pid = 0; + self->grandchild_pid = 0; } FIXTURE_TEARDOWN(nsid) { - /* Clean up any child process that may still be running */ + /* + * Kill grandchild first: timens_separate and pidns_separate fork a + * grandchild that calls pause(). It is reparented to init on child + * exit and keeps the test runner's tap pipe open, hanging the runner. + */ + if (self->grandchild_pid > 0) { + kill(self->grandchild_pid, SIGKILL); + waitpid(self->grandchild_pid, NULL, 0); + } if (self->child_pid > 0) { kill(self->child_pid, SIGKILL); waitpid(self->child_pid, NULL, 0); @@ -676,6 +686,7 @@ TEST_F(nsid, timens_separate) pid_t grandchild_pid; ASSERT_EQ(read(pipefd[0], &grandchild_pid, sizeof(grandchild_pid)), sizeof(grandchild_pid)); + self->grandchild_pid = grandchild_pid; close(pipefd[0]); /* Open grandchild's time namespace */ @@ -797,6 +808,7 @@ TEST_F(nsid, pidns_separate) pid_t grandchild_pid; ASSERT_EQ(read(pipefd[0], &grandchild_pid, sizeof(grandchild_pid)), sizeof(grandchild_pid)); + self->grandchild_pid = grandchild_pid; close(pipefd[0]); /* Open grandchild's PID namespace */ From f36ddf9317dc99019a498af3853d547de1f62e5f Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ricardo=20B=2E=20Marli=C3=A8re?= Date: Tue, 7 Apr 2026 11:35:46 -0300 Subject: [PATCH 2/3] selftests/namespaces: Fix waitpid race in listns_efault_test cleanup MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The efault tests spawn two categories of child processes: namespace children (each in its own mount namespace, for concurrent destruction) and an iterator child that calls listns() in a tight loop. The cleanup loop used waitpid(-1), which reaps any child in any order. If the iterator child exits early (e.g. because listns() returned ENOSYS) before all namespace children have been reaped, waitpid(-1) may consume it instead. The subsequent targeted waitpid(iter_pid) would then block indefinitely. Track the PIDs of the namespace children explicitly and use targeted waitpid() calls in the cleanup loop so the iterator child cannot be inadvertently reaped during namespace cleanup. Signed-off-by: Ricardo B. Marlière Link: https://patch.msgid.link/20260407-selftests-namespaces_fixes-v1-2-59109909d88b@suse.com Signed-off-by: Christian Brauner --- .../selftests/namespaces/listns_efault_test.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/tools/testing/selftests/namespaces/listns_efault_test.c b/tools/testing/selftests/namespaces/listns_efault_test.c index b570746e917c..8df5397adbb0 100644 --- a/tools/testing/selftests/namespaces/listns_efault_test.c +++ b/tools/testing/selftests/namespaces/listns_efault_test.c @@ -38,7 +38,7 @@ TEST(listns_partial_fault_with_ns_cleanup) __u64 *ns_ids; ssize_t ret; long page_size; - pid_t pid, iter_pid; + pid_t pid, iter_pid, ns_pids[5]; int pidfds[5]; int sv[5][2]; int iter_pidfd; @@ -114,6 +114,7 @@ TEST(listns_partial_fault_with_ns_cleanup) pid = create_child(&pidfds[i], CLONE_NEWNS); ASSERT_NE(pid, -1); + ns_pids[i] = pid; if (pid == 0) { close(sv[i][0]); /* Close parent end */ @@ -164,7 +165,7 @@ TEST(listns_partial_fault_with_ns_cleanup) /* Wait for all mount namespace children to exit and cleanup */ for (i = 0; i < 5; i++) { - waitpid(-1, NULL, 0); + waitpid(ns_pids[i], NULL, 0); close(sv[i][0]); close(pidfds[i]); } @@ -250,7 +251,7 @@ TEST(listns_late_fault_with_ns_cleanup) __u64 *ns_ids; ssize_t ret; long page_size; - pid_t pid, iter_pid; + pid_t pid, iter_pid, ns_pids[10]; int pidfds[10]; int sv[10][2]; int iter_pidfd; @@ -320,6 +321,7 @@ TEST(listns_late_fault_with_ns_cleanup) pid = create_child(&pidfds[i], CLONE_NEWNS); ASSERT_NE(pid, -1); + ns_pids[i] = pid; if (pid == 0) { close(sv[i][0]); /* Close parent end */ @@ -373,7 +375,7 @@ TEST(listns_late_fault_with_ns_cleanup) /* Wait for all children and cleanup */ for (i = 0; i < 10; i++) { - waitpid(-1, NULL, 0); + waitpid(ns_pids[i], NULL, 0); close(sv[i][0]); close(pidfds[i]); } @@ -402,7 +404,7 @@ TEST(listns_mnt_ns_cleanup_on_fault) __u64 *ns_ids; ssize_t ret; long page_size; - pid_t pid, iter_pid; + pid_t pid, iter_pid, ns_pids[8]; int pidfds[8]; int sv[8][2]; int iter_pidfd; @@ -462,6 +464,7 @@ TEST(listns_mnt_ns_cleanup_on_fault) pid = create_child(&pidfds[i], CLONE_NEWNS); ASSERT_NE(pid, -1); + ns_pids[i] = pid; if (pid == 0) { close(sv[i][0]); /* Close parent end */ @@ -508,7 +511,7 @@ TEST(listns_mnt_ns_cleanup_on_fault) /* Wait for children and cleanup */ for (i = 0; i < 8; i++) { - waitpid(-1, NULL, 0); + waitpid(ns_pids[i], NULL, 0); close(sv[i][0]); close(pidfds[i]); } From 2509bdc8a47c2f13471ac43ec989c778ed304d77 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ricardo=20B=2E=20Marli=C3=A8re?= Date: Tue, 7 Apr 2026 11:35:47 -0300 Subject: [PATCH 3/3] selftests/namespaces: Skip efault tests when listns() is not available MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When listns() is not implemented the iterator child detects ENOSYS and exits cleanly with status PIDFD_SKIP before the parent has a chance to signal it. The parent sends SIGKILL (which is a harmless no-op at that point) and then calls waitpid(), obtaining a normal-exit status. The subsequent ASSERT_TRUE(WIFSIGNALED(status)) therefore fails, causing the three EFAULT-focused tests to report FAIL rather than SKIP on kernels that do not yet carry listns() support. After collecting the iterator's exit status, check whether it exited with PIDFD_SKIP and issue a SKIP verdict in that case, consistent with the behaviour of every other listns test that already handles ENOSYS correctly. Signed-off-by: Ricardo B. Marlière Link: https://patch.msgid.link/20260407-selftests-namespaces_fixes-v1-3-59109909d88b@suse.com Signed-off-by: Christian Brauner --- .../selftests/namespaces/listns_efault_test.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/tools/testing/selftests/namespaces/listns_efault_test.c b/tools/testing/selftests/namespaces/listns_efault_test.c index 8df5397adbb0..26b452c98c66 100644 --- a/tools/testing/selftests/namespaces/listns_efault_test.c +++ b/tools/testing/selftests/namespaces/listns_efault_test.c @@ -176,6 +176,12 @@ TEST(listns_partial_fault_with_ns_cleanup) ASSERT_EQ(ret, iter_pid); close(iter_pidfd); + /* If listns() is not supported the iterator exits cleanly via ENOSYS */ + if (WIFEXITED(status) && WEXITSTATUS(status) == PIDFD_SKIP) { + munmap(map, page_size); + SKIP(return, "listns() not supported"); + } + /* Should have been killed */ ASSERT_TRUE(WIFSIGNALED(status)); ASSERT_EQ(WTERMSIG(status), SIGKILL); @@ -386,6 +392,12 @@ TEST(listns_late_fault_with_ns_cleanup) ASSERT_EQ(ret, iter_pid); close(iter_pidfd); + /* If listns() is not supported the iterator exits cleanly via ENOSYS */ + if (WIFEXITED(status) && WEXITSTATUS(status) == PIDFD_SKIP) { + munmap(map, page_size); + SKIP(return, "listns() not supported"); + } + /* Should have been killed */ ASSERT_TRUE(WIFSIGNALED(status)); ASSERT_EQ(WTERMSIG(status), SIGKILL); @@ -522,6 +534,12 @@ TEST(listns_mnt_ns_cleanup_on_fault) ASSERT_EQ(ret, iter_pid); close(iter_pidfd); + /* If listns() is not supported the iterator exits cleanly via ENOSYS */ + if (WIFEXITED(status) && WEXITSTATUS(status) == PIDFD_SKIP) { + munmap(map, page_size); + SKIP(return, "listns() not supported"); + } + /* Should have been killed */ ASSERT_TRUE(WIFSIGNALED(status)); ASSERT_EQ(WTERMSIG(status), SIGKILL);