selftests: add pid namespace ENOMEM regression test

We recently regressed (cf. [1] and its corresponding fix in [2]) returning
ENOMEM when trying to create a process in a pid namespace whose init
process/child subreaper has already died. This has caused confusion at
least once before that (cf. [3]). Let's add a simple regression test to
catch this in the future.

[1]: 49cb2fc42c ("fork: extend clone3() to support setting a PID")
[2]: b26ebfe12f ("pid: Fix error return value in some cases")
[3]: 35f71bc0a0 ("fork: report pid reservation failure properly")
Cc: Corey Minyard <cminyard@mvista.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Adrian Reber <areber@redhat.com>
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: Andrei Vagin <avagin@gmail.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
This commit is contained in:
Christian Brauner 2020-03-08 17:26:32 +01:00
parent 2c523b344d
commit 6952a4f646
No known key found for this signature in database
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7 changed files with 60 additions and 0 deletions

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@ -13158,6 +13158,7 @@ S: Maintained
T: git git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux.git
F: samples/pidfd/
F: tools/testing/selftests/pidfd/
F: tools/testing/selftests/pid_namespace/
F: tools/testing/selftests/clone3/
K: (?i)pidfd
K: (?i)clone3

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@ -38,6 +38,7 @@ TARGETS += netfilter
TARGETS += networking/timestamping
TARGETS += nsfs
TARGETS += pidfd
TARGETS += pid_namespace
TARGETS += powerpc
TARGETS += proc
TARGETS += pstore

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@ -0,0 +1 @@
regression_enomem

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@ -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

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@ -0,0 +1,2 @@
CONFIG_PID_NS=y
CONFIG_USER_NS=y

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@ -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

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@ -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"