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authorLinus Torvalds <torvalds@linux-foundation.org>2019-09-16 09:28:19 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-09-16 09:28:19 -0700
commitc17112a5c413f20188da276c138484e7127cdc84 (patch)
tree9fb0607a64e4dd49bbf405ed456221640fa972d8 /tools
parent4d856f72c10ecb060868ed10ff1b1453943fc6c8 (diff)
parent821cc7b0b205c0df64cce59aacc330af251fa8f7 (diff)
Merge tag 'core-process-v5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux
Pull pidfd/waitid updates from Christian Brauner: "This contains two features and various tests. First, it adds support for waiting on process through pidfds by adding the P_PIDFD type to the waitid() syscall. This completes the basic functionality of the pidfd api (cf. [1]). In the meantime we also have a new adition to the userspace projects that make use of the pidfd api. The qt project was nice enough to send a mail pointing out that they have a pr up to switch to the pidfd api (cf. [2]). Second, this tag contains an extension to the waitid() syscall to make it possible to wait on the current process group in a race free manner (even though the actual problem is very unlikely) by specifing 0 together with the P_PGID type. This extension traces back to a discussion on the glibc development mailing list. There are also a range of tests for the features above. Additionally, the test-suite which detected the pidfd-polling race we fixed in [3] is included in this tag" [1] https://lwn.net/Articles/794707/ [2] https://codereview.qt-project.org/c/qt/qtbase/+/108456 [3] commit b191d6491be6 ("pidfd: fix a poll race when setting exit_state") * tag 'core-process-v5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux: waitid: Add support for waiting for the current process group tests: add pidfd poll tests tests: move common definitions and functions into pidfd.h pidfd: add pidfd_wait tests pidfd: add P_PIDFD to waitid()
Diffstat (limited to 'tools')
-rw-r--r--tools/testing/selftests/pidfd/.gitignore2
-rw-r--r--tools/testing/selftests/pidfd/Makefile2
-rw-r--r--tools/testing/selftests/pidfd/pidfd.h30
-rw-r--r--tools/testing/selftests/pidfd/pidfd_open_test.c5
-rw-r--r--tools/testing/selftests/pidfd/pidfd_poll_test.c117
-rw-r--r--tools/testing/selftests/pidfd/pidfd_test.c14
-rw-r--r--tools/testing/selftests/pidfd/pidfd_wait.c271
7 files changed, 421 insertions, 20 deletions
diff --git a/tools/testing/selftests/pidfd/.gitignore b/tools/testing/selftests/pidfd/.gitignore
index 16d84d117bc0..8d069490e17b 100644
--- a/tools/testing/selftests/pidfd/.gitignore
+++ b/tools/testing/selftests/pidfd/.gitignore
@@ -1,2 +1,4 @@
pidfd_open_test
+pidfd_poll_test
pidfd_test
+pidfd_wait
diff --git a/tools/testing/selftests/pidfd/Makefile b/tools/testing/selftests/pidfd/Makefile
index 720b2d884b3c..464c9b76148f 100644
--- a/tools/testing/selftests/pidfd/Makefile
+++ b/tools/testing/selftests/pidfd/Makefile
@@ -1,7 +1,7 @@
# SPDX-License-Identifier: GPL-2.0-only
CFLAGS += -g -I../../../../usr/include/ -lpthread
-TEST_GEN_PROGS := pidfd_test pidfd_open_test
+TEST_GEN_PROGS := pidfd_test pidfd_open_test pidfd_poll_test pidfd_wait
include ../lib.mk
diff --git a/tools/testing/selftests/pidfd/pidfd.h b/tools/testing/selftests/pidfd/pidfd.h
index 8452e910463f..c6bc68329f4b 100644
--- a/tools/testing/selftests/pidfd/pidfd.h
+++ b/tools/testing/selftests/pidfd/pidfd.h
@@ -16,6 +16,26 @@
#include "../kselftest.h"
+#ifndef P_PIDFD
+#define P_PIDFD 3
+#endif
+
+#ifndef CLONE_PIDFD
+#define CLONE_PIDFD 0x00001000
+#endif
+
+#ifndef __NR_pidfd_open
+#define __NR_pidfd_open -1
+#endif
+
+#ifndef __NR_pidfd_send_signal
+#define __NR_pidfd_send_signal -1
+#endif
+
+#ifndef __NR_clone3
+#define __NR_clone3 -1
+#endif
+
/*
* The kernel reserves 300 pids via RESERVED_PIDS in kernel/pid.c
* That means, when it wraps around any pid < 300 will be skipped.
@@ -53,5 +73,15 @@ again:
return WEXITSTATUS(status);
}
+static inline int sys_pidfd_open(pid_t pid, unsigned int flags)
+{
+ return syscall(__NR_pidfd_open, pid, flags);
+}
+
+static inline int sys_pidfd_send_signal(int pidfd, int sig, siginfo_t *info,
+ unsigned int flags)
+{
+ return syscall(__NR_pidfd_send_signal, pidfd, sig, info, flags);
+}
#endif /* __PIDFD_H */
diff --git a/tools/testing/selftests/pidfd/pidfd_open_test.c b/tools/testing/selftests/pidfd/pidfd_open_test.c
index 0377133dd6dc..b9fe75fc3e51 100644
--- a/tools/testing/selftests/pidfd/pidfd_open_test.c
+++ b/tools/testing/selftests/pidfd/pidfd_open_test.c
@@ -22,11 +22,6 @@
#include "pidfd.h"
#include "../kselftest.h"
-static inline int sys_pidfd_open(pid_t pid, unsigned int flags)
-{
- return syscall(__NR_pidfd_open, pid, flags);
-}
-
static int safe_int(const char *numstr, int *converted)
{
char *err = NULL;
diff --git a/tools/testing/selftests/pidfd/pidfd_poll_test.c b/tools/testing/selftests/pidfd/pidfd_poll_test.c
new file mode 100644
index 000000000000..4b115444dfe9
--- /dev/null
+++ b/tools/testing/selftests/pidfd/pidfd_poll_test.c
@@ -0,0 +1,117 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#define _GNU_SOURCE
+#include <errno.h>
+#include <linux/types.h>
+#include <linux/wait.h>
+#include <poll.h>
+#include <signal.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <syscall.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include "pidfd.h"
+#include "../kselftest.h"
+
+static bool timeout;
+
+static void handle_alarm(int sig)
+{
+ timeout = true;
+}
+
+int main(int argc, char **argv)
+{
+ struct pollfd fds;
+ int iter, nevents;
+ int nr_iterations = 10000;
+
+ fds.events = POLLIN;
+
+ if (argc > 2)
+ ksft_exit_fail_msg("Unexpected command line argument\n");
+
+ if (argc == 2) {
+ nr_iterations = atoi(argv[1]);
+ if (nr_iterations <= 0)
+ ksft_exit_fail_msg("invalid input parameter %s\n",
+ argv[1]);
+ }
+
+ ksft_print_msg("running pidfd poll test for %d iterations\n",
+ nr_iterations);
+
+ for (iter = 0; iter < nr_iterations; iter++) {
+ int pidfd;
+ int child_pid = fork();
+
+ if (child_pid < 0) {
+ if (errno == EAGAIN) {
+ iter--;
+ continue;
+ }
+ ksft_exit_fail_msg(
+ "%s - failed to fork a child process\n",
+ strerror(errno));
+ }
+
+ if (child_pid == 0) {
+ /* Child process just sleeps for a min and exits */
+ sleep(60);
+ exit(EXIT_SUCCESS);
+ }
+
+ /* Parent kills the child and waits for its death */
+ pidfd = sys_pidfd_open(child_pid, 0);
+ if (pidfd < 0)
+ ksft_exit_fail_msg("%s - pidfd_open failed\n",
+ strerror(errno));
+
+ /* Setup 3 sec alarm - plenty of time */
+ if (signal(SIGALRM, handle_alarm) == SIG_ERR)
+ ksft_exit_fail_msg("%s - signal failed\n",
+ strerror(errno));
+ alarm(3);
+
+ /* Send SIGKILL to the child */
+ if (sys_pidfd_send_signal(pidfd, SIGKILL, NULL, 0))
+ ksft_exit_fail_msg("%s - pidfd_send_signal failed\n",
+ strerror(errno));
+
+ /* Wait for the death notification */
+ fds.fd = pidfd;
+ nevents = poll(&fds, 1, -1);
+
+ /* Check for error conditions */
+ if (nevents < 0)
+ ksft_exit_fail_msg("%s - poll failed\n",
+ strerror(errno));
+
+ if (nevents != 1)
+ ksft_exit_fail_msg("unexpected poll result: %d\n",
+ nevents);
+
+ if (!(fds.revents & POLLIN))
+ ksft_exit_fail_msg(
+ "unexpected event type received: 0x%x\n",
+ fds.revents);
+
+ if (timeout)
+ ksft_exit_fail_msg(
+ "death notification wait timeout\n");
+
+ close(pidfd);
+ /* Wait for child to prevent zombies */
+ if (waitpid(child_pid, NULL, 0) < 0)
+ ksft_exit_fail_msg("%s - waitpid failed\n",
+ strerror(errno));
+
+ }
+
+ ksft_test_result_pass("pidfd poll test: pass\n");
+ return ksft_exit_pass();
+}
diff --git a/tools/testing/selftests/pidfd/pidfd_test.c b/tools/testing/selftests/pidfd/pidfd_test.c
index b632965e60eb..7aff2d3b42c0 100644
--- a/tools/testing/selftests/pidfd/pidfd_test.c
+++ b/tools/testing/selftests/pidfd/pidfd_test.c
@@ -21,20 +21,12 @@
#include "pidfd.h"
#include "../kselftest.h"
-#ifndef __NR_pidfd_send_signal
-#define __NR_pidfd_send_signal -1
-#endif
-
#define str(s) _str(s)
#define _str(s) #s
#define CHILD_THREAD_MIN_WAIT 3 /* seconds */
#define MAX_EVENTS 5
-#ifndef CLONE_PIDFD
-#define CLONE_PIDFD 0x00001000
-#endif
-
static pid_t pidfd_clone(int flags, int *pidfd, int (*fn)(void *))
{
size_t stack_size = 1024;
@@ -47,12 +39,6 @@ static pid_t pidfd_clone(int flags, int *pidfd, int (*fn)(void *))
#endif
}
-static inline int sys_pidfd_send_signal(int pidfd, int sig, siginfo_t *info,
- unsigned int flags)
-{
- return syscall(__NR_pidfd_send_signal, pidfd, sig, info, flags);
-}
-
static int signal_received;
static void set_signal_received_on_sigusr1(int sig)
diff --git a/tools/testing/selftests/pidfd/pidfd_wait.c b/tools/testing/selftests/pidfd/pidfd_wait.c
new file mode 100644
index 000000000000..7079f8eef792
--- /dev/null
+++ b/tools/testing/selftests/pidfd/pidfd_wait.c
@@ -0,0 +1,271 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#define _GNU_SOURCE
+#include <errno.h>
+#include <linux/sched.h>
+#include <linux/types.h>
+#include <signal.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sched.h>
+#include <string.h>
+#include <sys/resource.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include "pidfd.h"
+#include "../kselftest.h"
+
+#define ptr_to_u64(ptr) ((__u64)((uintptr_t)(ptr)))
+
+static pid_t sys_clone3(struct clone_args *args)
+{
+ return syscall(__NR_clone3, args, sizeof(struct clone_args));
+}
+
+static int sys_waitid(int which, pid_t pid, siginfo_t *info, int options,
+ struct rusage *ru)
+{
+ return syscall(__NR_waitid, which, pid, info, options, ru);
+}
+
+static int test_pidfd_wait_simple(void)
+{
+ const char *test_name = "pidfd wait simple";
+ int pidfd = -1, status = 0;
+ pid_t parent_tid = -1;
+ struct clone_args args = {
+ .parent_tid = ptr_to_u64(&parent_tid),
+ .pidfd = ptr_to_u64(&pidfd),
+ .flags = CLONE_PIDFD | CLONE_PARENT_SETTID,
+ .exit_signal = SIGCHLD,
+ };
+ int ret;
+ pid_t pid;
+ siginfo_t info = {
+ .si_signo = 0,
+ };
+
+ pidfd = open("/proc/self", O_DIRECTORY | O_RDONLY | O_CLOEXEC);
+ if (pidfd < 0)
+ ksft_exit_fail_msg("%s test: failed to open /proc/self %s\n",
+ test_name, strerror(errno));
+
+ pid = sys_waitid(P_PIDFD, pidfd, &info, WEXITED, NULL);
+ if (pid == 0)
+ ksft_exit_fail_msg(
+ "%s test: succeeded to wait on invalid pidfd %s\n",
+ test_name, strerror(errno));
+ close(pidfd);
+ pidfd = -1;
+
+ pidfd = open("/dev/null", O_RDONLY | O_CLOEXEC);
+ if (pidfd == 0)
+ ksft_exit_fail_msg("%s test: failed to open /dev/null %s\n",
+ test_name, strerror(errno));
+
+ pid = sys_waitid(P_PIDFD, pidfd, &info, WEXITED, NULL);
+ if (pid == 0)
+ ksft_exit_fail_msg(
+ "%s test: succeeded to wait on invalid pidfd %s\n",
+ test_name, strerror(errno));
+ close(pidfd);
+ pidfd = -1;
+
+ pid = sys_clone3(&args);
+ if (pid < 0)
+ ksft_exit_fail_msg("%s test: failed to create new process %s\n",
+ test_name, strerror(errno));
+
+ if (pid == 0)
+ exit(EXIT_SUCCESS);
+
+ pid = sys_waitid(P_PIDFD, pidfd, &info, WEXITED, NULL);
+ if (pid < 0)
+ ksft_exit_fail_msg(
+ "%s test: failed to wait on process with pid %d and pidfd %d: %s\n",
+ test_name, parent_tid, pidfd, strerror(errno));
+
+ if (!WIFEXITED(info.si_status) || WEXITSTATUS(info.si_status))
+ ksft_exit_fail_msg(
+ "%s test: unexpected status received after waiting on process with pid %d and pidfd %d: %s\n",
+ test_name, parent_tid, pidfd, strerror(errno));
+ close(pidfd);
+
+ if (info.si_signo != SIGCHLD)
+ ksft_exit_fail_msg(
+ "%s test: unexpected si_signo value %d received after waiting on process with pid %d and pidfd %d: %s\n",
+ test_name, info.si_signo, parent_tid, pidfd,
+ strerror(errno));
+
+ if (info.si_code != CLD_EXITED)
+ ksft_exit_fail_msg(
+ "%s test: unexpected si_code value %d received after waiting on process with pid %d and pidfd %d: %s\n",
+ test_name, info.si_code, parent_tid, pidfd,
+ strerror(errno));
+
+ if (info.si_pid != parent_tid)
+ ksft_exit_fail_msg(
+ "%s test: unexpected si_pid value %d received after waiting on process with pid %d and pidfd %d: %s\n",
+ test_name, info.si_pid, parent_tid, pidfd,
+ strerror(errno));
+
+ ksft_test_result_pass("%s test: Passed\n", test_name);
+ return 0;
+}
+
+static int test_pidfd_wait_states(void)
+{
+ const char *test_name = "pidfd wait states";
+ int pidfd = -1, status = 0;
+ pid_t parent_tid = -1;
+ struct clone_args args = {
+ .parent_tid = ptr_to_u64(&parent_tid),
+ .pidfd = ptr_to_u64(&pidfd),
+ .flags = CLONE_PIDFD | CLONE_PARENT_SETTID,
+ .exit_signal = SIGCHLD,
+ };
+ int ret;
+ pid_t pid;
+ siginfo_t info = {
+ .si_signo = 0,
+ };
+
+ pid = sys_clone3(&args);
+ if (pid < 0)
+ ksft_exit_fail_msg("%s test: failed to create new process %s\n",
+ test_name, strerror(errno));
+
+ if (pid == 0) {
+ kill(getpid(), SIGSTOP);
+ kill(getpid(), SIGSTOP);
+ exit(EXIT_SUCCESS);
+ }
+
+ ret = sys_waitid(P_PIDFD, pidfd, &info, WSTOPPED, NULL);
+ if (ret < 0)
+ ksft_exit_fail_msg(
+ "%s test: failed to wait on WSTOPPED process with pid %d and pidfd %d: %s\n",
+ test_name, parent_tid, pidfd, strerror(errno));
+
+ if (info.si_signo != SIGCHLD)
+ ksft_exit_fail_msg(
+ "%s test: unexpected si_signo value %d received after waiting on process with pid %d and pidfd %d: %s\n",
+ test_name, info.si_signo, parent_tid, pidfd,
+ strerror(errno));
+
+ if (info.si_code != CLD_STOPPED)
+ ksft_exit_fail_msg(
+ "%s test: unexpected si_code value %d received after waiting on process with pid %d and pidfd %d: %s\n",
+ test_name, info.si_code, parent_tid, pidfd,
+ strerror(errno));
+
+ if (info.si_pid != parent_tid)
+ ksft_exit_fail_msg(
+ "%s test: unexpected si_pid value %d received after waiting on process with pid %d and pidfd %d: %s\n",
+ test_name, info.si_pid, parent_tid, pidfd,
+ strerror(errno));
+
+ ret = sys_pidfd_send_signal(pidfd, SIGCONT, NULL, 0);
+ if (ret < 0)
+ ksft_exit_fail_msg(
+ "%s test: failed to send signal to process with pid %d and pidfd %d: %s\n",
+ test_name, parent_tid, pidfd, strerror(errno));
+
+ ret = sys_waitid(P_PIDFD, pidfd, &info, WCONTINUED, NULL);
+ if (ret < 0)
+ ksft_exit_fail_msg(
+ "%s test: failed to wait WCONTINUED on process with pid %d and pidfd %d: %s\n",
+ test_name, parent_tid, pidfd, strerror(errno));
+
+ if (info.si_signo != SIGCHLD)
+ ksft_exit_fail_msg(
+ "%s test: unexpected si_signo value %d received after waiting on process with pid %d and pidfd %d: %s\n",
+ test_name, info.si_signo, parent_tid, pidfd,
+ strerror(errno));
+
+ if (info.si_code != CLD_CONTINUED)
+ ksft_exit_fail_msg(
+ "%s test: unexpected si_code value %d received after waiting on process with pid %d and pidfd %d: %s\n",
+ test_name, info.si_code, parent_tid, pidfd,
+ strerror(errno));
+
+ if (info.si_pid != parent_tid)
+ ksft_exit_fail_msg(
+ "%s test: unexpected si_pid value %d received after waiting on process with pid %d and pidfd %d: %s\n",
+ test_name, info.si_pid, parent_tid, pidfd,
+ strerror(errno));
+
+ ret = sys_waitid(P_PIDFD, pidfd, &info, WUNTRACED, NULL);
+ if (ret < 0)
+ ksft_exit_fail_msg(
+ "%s test: failed to wait on WUNTRACED process with pid %d and pidfd %d: %s\n",
+ test_name, parent_tid, pidfd, strerror(errno));
+
+ if (info.si_signo != SIGCHLD)
+ ksft_exit_fail_msg(
+ "%s test: unexpected si_signo value %d received after waiting on process with pid %d and pidfd %d: %s\n",
+ test_name, info.si_signo, parent_tid, pidfd,
+ strerror(errno));
+
+ if (info.si_code != CLD_STOPPED)
+ ksft_exit_fail_msg(
+ "%s test: unexpected si_code value %d received after waiting on process with pid %d and pidfd %d: %s\n",
+ test_name, info.si_code, parent_tid, pidfd,
+ strerror(errno));
+
+ if (info.si_pid != parent_tid)
+ ksft_exit_fail_msg(
+ "%s test: unexpected si_pid value %d received after waiting on process with pid %d and pidfd %d: %s\n",
+ test_name, info.si_pid, parent_tid, pidfd,
+ strerror(errno));
+
+ ret = sys_pidfd_send_signal(pidfd, SIGKILL, NULL, 0);
+ if (ret < 0)
+ ksft_exit_fail_msg(
+ "%s test: failed to send SIGKILL to process with pid %d and pidfd %d: %s\n",
+ test_name, parent_tid, pidfd, strerror(errno));
+
+ ret = sys_waitid(P_PIDFD, pidfd, &info, WEXITED, NULL);
+ if (ret < 0)
+ ksft_exit_fail_msg(
+ "%s test: failed to wait on WEXITED process with pid %d and pidfd %d: %s\n",
+ test_name, parent_tid, pidfd, strerror(errno));
+
+ if (info.si_signo != SIGCHLD)
+ ksft_exit_fail_msg(
+ "%s test: unexpected si_signo value %d received after waiting on process with pid %d and pidfd %d: %s\n",
+ test_name, info.si_signo, parent_tid, pidfd,
+ strerror(errno));
+
+ if (info.si_code != CLD_KILLED)
+ ksft_exit_fail_msg(
+ "%s test: unexpected si_code value %d received after waiting on process with pid %d and pidfd %d: %s\n",
+ test_name, info.si_code, parent_tid, pidfd,
+ strerror(errno));
+
+ if (info.si_pid != parent_tid)
+ ksft_exit_fail_msg(
+ "%s test: unexpected si_pid value %d received after waiting on process with pid %d and pidfd %d: %s\n",
+ test_name, info.si_pid, parent_tid, pidfd,
+ strerror(errno));
+
+ close(pidfd);
+
+ ksft_test_result_pass("%s test: Passed\n", test_name);
+ return 0;
+}
+
+int main(int argc, char **argv)
+{
+ ksft_print_header();
+ ksft_set_plan(2);
+
+ test_pidfd_wait_simple();
+ test_pidfd_wait_states();
+
+ return ksft_exit_pass();
+}