Merge tag 'threads-v5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux

Pull thread updates from Christian Brauner:
 "The main change for this cycle was the extension for clone3() to
  support spawning processes directly into cgroups via CLONE_INTO_CGROUP
  (commit ef2c41cf38a7: "clone3: allow spawning processes
  into cgroups").

  But since I had to touch kernel/cgroup/ quite a bit I had Tejun route
  that through his tree this time around to make it easier for him to
  handle other changes.

  So here is just the unexciting leftovers: a regression test for the
  ENOMEM regression we fixed in commit b26ebfe12f34 ("pid: Fix error
  return value in some cases") verifying that we report ENOMEM when
  trying to create a new process in a pid namespace whose init
  process/subreaper has already exited"

* tag 'threads-v5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux:
  selftests: add pid namespace ENOMEM regression test

6 files changed, 59 insertions, 0 deletions

diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index 0635684cbf07..2ff68702fd41 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -38,6 +38,7 @@ TARGETS += net/mptcp
 TARGETS += netfilter
 TARGETS += nsfs
 TARGETS += pidfd
+TARGETS += pid_namespace
 TARGETS += powerpc
 TARGETS += proc
 TARGETS += pstore
diff --git a/tools/testing/selftests/pid_namespace/.gitignore b/tools/testing/selftests/pid_namespace/.gitignore
new file mode 100644
index 000000000000..93ab9d7e5b7e
--- /dev/null
+++ b/tools/testing/selftests/pid_namespace/.gitignore
@@ -0,0 +1 @@
+regression_enomem
diff --git a/tools/testing/selftests/pid_namespace/Makefile b/tools/testing/selftests/pid_namespace/Makefile
new file mode 100644
index 000000000000..dcaefa224ca0
--- /dev/null
+++ b/tools/testing/selftests/pid_namespace/Makefile
@@ -0,0 +1,8 @@
+# SPDX-License-Identifier: GPL-2.0
+CFLAGS += -g -I../../../../usr/include/
+
+TEST_GEN_PROGS := regression_enomem
+
+include ../lib.mk
+
+$(OUTPUT)/regression_enomem: regression_enomem.c ../pidfd/pidfd.h
diff --git a/tools/testing/selftests/pid_namespace/config b/tools/testing/selftests/pid_namespace/config
new file mode 100644
index 000000000000..26cdb27e7dbb
--- /dev/null
+++ b/tools/testing/selftests/pid_namespace/config
@@ -0,0 +1,2 @@
+CONFIG_PID_NS=y
+CONFIG_USER_NS=y
diff --git a/tools/testing/selftests/pid_namespace/regression_enomem.c b/tools/testing/selftests/pid_namespace/regression_enomem.c
new file mode 100644
index 000000000000..73d532556d17
--- /dev/null
+++ b/tools/testing/selftests/pid_namespace/regression_enomem.c
@@ -0,0 +1,45 @@
+#define _GNU_SOURCE
+#include <assert.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/types.h>
+#include <sched.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <syscall.h>
+#include <sys/wait.h>
+
+#include "../kselftest.h"
+#include "../kselftest_harness.h"
+#include "../pidfd/pidfd.h"
+
+/*
+ * Regression test for:
+ * 35f71bc0a09a ("fork: report pid reservation failure properly")
+ * b26ebfe12f34 ("pid: Fix error return value in some cases")
+ */
+TEST(regression_enomem)
+{
+	pid_t pid;
+
+	if (geteuid())
+		EXPECT_EQ(0, unshare(CLONE_NEWUSER));
+
+	EXPECT_EQ(0, unshare(CLONE_NEWPID));
+
+	pid = fork();
+	ASSERT_GE(pid, 0);
+
+	if (pid == 0)
+		exit(EXIT_SUCCESS);
+
+	EXPECT_EQ(0, wait_for_pid(pid));
+
+	pid = fork();
+	ASSERT_LT(pid, 0);
+	ASSERT_EQ(errno, ENOMEM);
+}
+
+TEST_HARNESS_MAIN
diff --git a/tools/testing/selftests/pidfd/pidfd.h b/tools/testing/selftests/pidfd/pidfd.h
index d482515604db..c1921a53dbed 100644
--- a/tools/testing/selftests/pidfd/pidfd.h
+++ b/tools/testing/selftests/pidfd/pidfd.h
@@ -13,6 +13,8 @@
 #include <string.h>
 #include <syscall.h>
 #include <sys/mount.h>
+#include <sys/types.h>
+#include <sys/wait.h>
 
 #include "../kselftest.h"