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selftests/pidfd: add first PIDFD_INFO_EXIT selftest
Add a selftest for PIDFD_INFO_EXIT behavior. Link: https://lore.kernel.org/r/20250305-work-pidfs-kill_on_last_close-v3-10-c8c3d8361705@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org>
1 parent ddf5315 commit 853ab1f

4 files changed

Lines changed: 153 additions & 2 deletions

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‎tools/testing/selftests/pidfd/.gitignore‎

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@@ -8,3 +8,4 @@ pidfd_getfd_test
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pidfd_setns_test
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pidfd_file_handle_test
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pidfd_bind_mount
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pidfd_info_test

‎tools/testing/selftests/pidfd/Makefile‎

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@@ -3,7 +3,7 @@ CFLAGS += -g $(KHDR_INCLUDES) -pthread -Wall
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TEST_GEN_PROGS := pidfd_test pidfd_fdinfo_test pidfd_open_test \
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pidfd_poll_test pidfd_wait pidfd_getfd_test pidfd_setns_test \
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pidfd_file_handle_test pidfd_bind_mount
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pidfd_file_handle_test pidfd_bind_mount pidfd_info_test
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include ../lib.mk
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‎tools/testing/selftests/pidfd/pidfd.h‎

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@@ -127,6 +127,10 @@
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#define PIDFD_INFO_CGROUPID (1UL << 2) /* Always returned if available, even if not requested */
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#endif
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#ifndef PIDFD_INFO_EXIT
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#define PIDFD_INFO_EXIT (1UL << 3) /* Always returned if available, even if not requested */
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#endif
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struct pidfd_info {
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__u64 mask;
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__u64 cgroupid;
@@ -141,7 +145,7 @@ struct pidfd_info {
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__u32 sgid;
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__u32 fsuid;
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__u32 fsgid;
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__u32 spare0[1];
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__s32 exit_code;
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};
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/*

‎tools/testing/selftests/pidfd/pidfd_info_test.c‎

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// SPDX-License-Identifier: GPL-2.0
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#define _GNU_SOURCE
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#include <errno.h>
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#include <fcntl.h>
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#include <limits.h>
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#include <linux/types.h>
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#include <poll.h>
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#include <pthread.h>
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#include <sched.h>
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#include <signal.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <syscall.h>
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#include <sys/prctl.h>
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#include <sys/wait.h>
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#include <unistd.h>
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#include <sys/socket.h>
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#include <linux/kcmp.h>
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#include <sys/stat.h>
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#include "pidfd.h"
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#include "../kselftest_harness.h"
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FIXTURE(pidfd_info)
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{
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pid_t child_pid1;
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int child_pidfd1;
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pid_t child_pid2;
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int child_pidfd2;
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pid_t child_pid3;
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int child_pidfd3;
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pid_t child_pid4;
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int child_pidfd4;
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};
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FIXTURE_SETUP(pidfd_info)
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{
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int ret;
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int ipc_sockets[2];
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char c;
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ret = socketpair(AF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0, ipc_sockets);
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EXPECT_EQ(ret, 0);
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self->child_pid1 = create_child(&self->child_pidfd1, 0);
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EXPECT_GE(self->child_pid1, 0);
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if (self->child_pid1 == 0) {
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close(ipc_sockets[0]);
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if (write_nointr(ipc_sockets[1], "1", 1) < 0)
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_exit(EXIT_FAILURE);
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close(ipc_sockets[1]);
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pause();
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_exit(EXIT_SUCCESS);
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}
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EXPECT_EQ(close(ipc_sockets[1]), 0);
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ASSERT_EQ(read_nointr(ipc_sockets[0], &c, 1), 1);
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EXPECT_EQ(close(ipc_sockets[0]), 0);
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/* SIGKILL but don't reap. */
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EXPECT_EQ(sys_pidfd_send_signal(self->child_pidfd1, SIGKILL, NULL, 0), 0);
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ret = socketpair(AF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0, ipc_sockets);
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EXPECT_EQ(ret, 0);
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self->child_pid2 = create_child(&self->child_pidfd2, 0);
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EXPECT_GE(self->child_pid2, 0);
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if (self->child_pid2 == 0) {
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close(ipc_sockets[0]);
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if (write_nointr(ipc_sockets[1], "1", 1) < 0)
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_exit(EXIT_FAILURE);
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close(ipc_sockets[1]);
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pause();
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_exit(EXIT_SUCCESS);
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}
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EXPECT_EQ(close(ipc_sockets[1]), 0);
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ASSERT_EQ(read_nointr(ipc_sockets[0], &c, 1), 1);
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EXPECT_EQ(close(ipc_sockets[0]), 0);
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/* SIGKILL and reap. */
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EXPECT_EQ(sys_pidfd_send_signal(self->child_pidfd2, SIGKILL, NULL, 0), 0);
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EXPECT_EQ(sys_waitid(P_PID, self->child_pid2, NULL, WEXITED), 0);
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self->child_pid3 = create_child(&self->child_pidfd3, CLONE_NEWUSER | CLONE_NEWPID);
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EXPECT_GE(self->child_pid3, 0);
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if (self->child_pid3 == 0)
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_exit(EXIT_SUCCESS);
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self->child_pid4 = create_child(&self->child_pidfd4, CLONE_NEWUSER | CLONE_NEWPID);
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EXPECT_GE(self->child_pid4, 0);
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if (self->child_pid4 == 0)
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_exit(EXIT_SUCCESS);
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EXPECT_EQ(sys_waitid(P_PID, self->child_pid4, NULL, WEXITED), 0);
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}
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FIXTURE_TEARDOWN(pidfd_info)
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{
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sys_pidfd_send_signal(self->child_pidfd1, SIGKILL, NULL, 0);
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if (self->child_pidfd1 >= 0)
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EXPECT_EQ(0, close(self->child_pidfd1));
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sys_waitid(P_PID, self->child_pid1, NULL, WEXITED);
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sys_pidfd_send_signal(self->child_pidfd2, SIGKILL, NULL, 0);
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if (self->child_pidfd2 >= 0)
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EXPECT_EQ(0, close(self->child_pidfd2));
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sys_waitid(P_PID, self->child_pid2, NULL, WEXITED);
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sys_waitid(P_PID, self->child_pid3, NULL, WEXITED);
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sys_waitid(P_PID, self->child_pid4, NULL, WEXITED);
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}
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TEST_F(pidfd_info, sigkill_exit)
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{
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struct pidfd_info info = {
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.mask = PIDFD_INFO_CGROUPID,
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};
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/* Process has exited but not been reaped so this must work. */
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ASSERT_EQ(ioctl(self->child_pidfd1, PIDFD_GET_INFO, &info), 0);
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info.mask = PIDFD_INFO_CGROUPID | PIDFD_INFO_EXIT;
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ASSERT_EQ(ioctl(self->child_pidfd1, PIDFD_GET_INFO, &info), 0);
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ASSERT_TRUE(!!(info.mask & PIDFD_INFO_CREDS));
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/* Process has exited but not been reaped, so no PIDFD_INFO_EXIT information yet. */
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ASSERT_FALSE(!!(info.mask & PIDFD_INFO_EXIT));
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}
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TEST_HARNESS_MAIN

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