[Devel] [PATCH vz10 1/2] selftests: ve: grant the directories the files sit in

[Devel] [PATCH vz10 1/2] selftests: ve: grant the directories the files sit in

[Eva Kurchatova]

The sysfs variant names nested leaves, kernel/vmcoreinfo and
kernel/notes, while the proc one names files at the top of the
filesystem. Both enforcement tests grant the leaves and nothing else,
so in the sysfs case the lookup stops at /sys/kernel, which a fresh VE
cannot traverse, and every open answers ENOENT:

  not ok 14 ve_perms.sysfs.enforce_allows
  not ok 15 ve_perms.sysfs.enforce_denies

Grant x on each directory along the way, taken from the path the
variant already gives. A file at the top of the filesystem has none
and needs nothing, so the proc variant is unaffected.

The suite then passes 16 of 16, where it passed 14 before.

https://virtuozzo.atlassian.net/browse/VSTOR-144955

Feature: fix vz selftests
Signed-off-by: Eva Kurchatova <eva.kurchatova@virtuozzo.com>
---
 tools/testing/selftests/ve/ve_perms_test.c | 33 ++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/tools/testing/selftests/ve/ve_perms_test.c b/tools/testing/selftests/ve/ve_perms_test.c
index 25ffbd42c380..2b542dc30139 100644
--- a/tools/testing/selftests/ve/ve_perms_test.c
+++ b/tools/testing/selftests/ve/ve_perms_test.c
@@ -348,6 +348,37 @@ TEST_F(ve_perms, write_parser)
  * read, and granting x on the directory lets it be traversed (the lookup then
  * fails ENOENT on the missing child, not EACCES).
  */
+/*
+ * A leaf is only reachable once every directory above it can be traversed.
+ * The variants name their files relative to the mount point, so grant x on
+ * each directory along the way; a file at the top of the filesystem has
+ * none and needs nothing.
+ */
+static int allow_path(int cgv2_fd, const char *path, const char *file)
+{
+	char dir[240];	/* set_entry() writes "<dir> <mask>" into 256 */
+	const char *sep;
+
+	for (sep = strchr(file, '/'); sep; sep = strchr(sep + 1, '/')) {
+		if (sep - file >= (long)sizeof(dir))
+			return -1;
+		snprintf(dir, sizeof(dir), "%.*s", (int)(sep - file), file);
+		if (set_entry(cgv2_fd, path, dir, "x") < 0)
+			return -1;
+	}
+	return 0;
+}
+
+static int allow_paths(int cgv2_fd, const char *path, const char *const files[])
+{
+	int i;
+
+	for (i = 0; i < NR_FILES; i++)
+		if (allow_path(cgv2_fd, path, files[i]) < 0)
+			return -1;
+	return 0;
+}
+
 TEST_F(ve_perms, enforce_allows)
 {
 	char path[PATH_MAX], absent[128];
@@ -358,6 +389,7 @@ TEST_F(ve_perms, enforce_allows)
 
 	ve_file(path, sizeof(path), self->ctid_a, variant->fs);
 
+	ASSERT_EQ(allow_paths(self->cgv2_fd, path, variant->files), 0);
 	ASSERT_EQ(set_entries(self->cgv2_fd, path, variant->files, "r"), 0);
 	for (i = 0; i < NR_FILES; i++)
 		EXPECT_EQ(ve_open_rel(self->cgv2_fd, self->ctid_a,
@@ -400,6 +432,7 @@ TEST_F(ve_perms, enforce_denies)
 				      O_RDONLY), 0);
 
 	/* Granted w only: visible but not readable. */
+	ASSERT_EQ(allow_paths(self->cgv2_fd, path, variant->files), 0);
 	ASSERT_EQ(set_entries(self->cgv2_fd, path, variant->files, "w"), 0);
 	for (i = 0; i < NR_FILES; i++)
 		EXPECT_EQ(ve_open_rel(self->cgv2_fd, self->ctid_a,
-- 
2.55.0

_______________________________________________
Devel mailing list
Devel@openvz.org
https://lists.openvz.org/mailman/listinfo/devel

[Devel] [PATCH vz10 2/2] selftests: ve: introduce vtty pair teardown stress test

[Eva Kurchatova]

A vtty pair is created by the first master open and torn down by the
last close. The close racing the peer's close used to let both sides
decide they were the final one and call release_tty() twice, and a
master opening again while a teardown was in flight used to hand out a
reference to a tty_struct about to be freed.

Hammer both ends. The master comes from the vzctl ioctl, which does
not look the VE up. The slave is only reachable from inside the VE, as
TTY_MAJOR minor 1..MAX_NR_VTTY_CONSOLES, which vtty_driver() maps to
vttys index minor - 1, so the test builds a VE with cgroup2, sets
ve.veid to the cgroup it made, and runs the slave side there.

One of the symtoms of a buggy kernel is dmesg warning, not just an
eventual crash, so the test checks that. A crashed node should also
report test failure in CI, but that's less verbose, hence the check.

https://virtuozzo.atlassian.net/browse/VSTOR-144771

Feature: ve selftest
Signed-off-by: Eva Kurchatova <eva.kurchatova@virtuozzo.com>
---
 tools/testing/selftests/ve/Makefile         |   1 +
 tools/testing/selftests/ve/settings         |   1 +
 tools/testing/selftests/ve/ve_vtty_stress.c | 244 ++++++++++++++++++++
 3 files changed, 246 insertions(+)
 create mode 100644 tools/testing/selftests/ve/settings
 create mode 100644 tools/testing/selftests/ve/ve_vtty_stress.c

diff --git a/tools/testing/selftests/ve/Makefile b/tools/testing/selftests/ve/Makefile
index ec40cbc7b3a1..6cd5823c4d93 100644
--- a/tools/testing/selftests/ve/Makefile
+++ b/tools/testing/selftests/ve/Makefile
@@ -4,5 +4,6 @@ CFLAGS += -g -Wall -O2
 
 TEST_GEN_PROGS += ve_ns_owner_test
 TEST_GEN_PROGS += ve_perms_test
+TEST_GEN_PROGS += ve_vtty_stress
 
 include ../lib.mk
diff --git a/tools/testing/selftests/ve/settings b/tools/testing/selftests/ve/settings
new file mode 100644
index 000000000000..e2206265f67c
--- /dev/null
+++ b/tools/testing/selftests/ve/settings
@@ -0,0 +1 @@
+timeout=900
diff --git a/tools/testing/selftests/ve/ve_vtty_stress.c b/tools/testing/selftests/ve/ve_vtty_stress.c
new file mode 100644
index 000000000000..9037f731c58d
--- /dev/null
+++ b/tools/testing/selftests/ve/ve_vtty_stress.c
@@ -0,0 +1,244 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ve_vtty_stress - close a vtty pair from both ends at once.
+ *
+ * A vtty pair is created by the first master open and torn down by the
+ * last close.  A close racing the peer's close used to let both sides
+ * decide they were the final one and call release_tty() twice, and a
+ * master opened again while a teardown was still in flight used to hand
+ * out a reference to a tty_struct that was about to be freed.  Either
+ * way the next close walked freed memory.
+ *
+ * The master comes from the vzctl ioctl, which does not look the VE up.
+ * The slave is only reachable from inside the VE, as TTY_MAJOR minor
+ * 1..MAX_NR_VTTY_CONSOLES, which vtty_driver() maps to vttys index
+ * minor - 1.  So the test makes a VE with cgroup2, hammers the master
+ * from the host and the slave from a task inside it, and fails if the
+ * kernel logs a complaint about the teardown.
+ *
+ * Surviving is not a pass on its own: the first symptom is a warning,
+ * which stops nothing by itself.
+ *
+ * Usage: ve_vtty_stress [seconds]   (default 600, or $VE_VTTY_SECS)
+ */
+#define _GNU_SOURCE
+#include <sched.h>
+#include <stdbool.h>
+#include <sys/ioctl.h>
+#include <linux/major.h>
+#include <sys/sysmacros.h>
+#include <sys/wait.h>
+#include <time.h>
+
+#include "ve_selftest.h"
+#include "../kselftest.h"
+
+/* The ioctl argument; the trailing data[] the uapi struct has is unused. */
+struct vzctl_ve_configure {
+	unsigned int veid, key, val, size;
+};
+
+#define VZCTL_VE_CONFIGURE	_IOW('.', 15, struct vzctl_ve_configure)
+#define VE_CONFIGURE_OPEN_TTY	5
+
+#define VTTY_IDX	0		/* the pair both ends work on */
+#define SLAVE_MINOR	(VTTY_IDX + 1)	/* vtty_driver(): index = minor - 1 */
+#define DEFAULT_SECS	600
+
+static int open_master(int ctl_fd, unsigned int veid)
+{
+	struct vzctl_ve_configure c = {
+		.veid = veid, .key = VE_CONFIGURE_OPEN_TTY, .val = VTTY_IDX,
+	};
+
+	return ioctl(ctl_fd, VZCTL_VE_CONFIGURE, &c);
+}
+
+/*
+ * The slave end, inside the VE.  Every error here is one the race is
+ * expected to produce: the pair is gone once the master has closed it.
+ */
+static int hammer_slave(time_t deadline, unsigned long *opened)
+{
+	char node[] = "/tmp/ve_vtty_slave";
+
+	unlink(node);
+	if (mknod(node, S_IFCHR | 0600, makedev(TTY_MAJOR, SLAVE_MINOR)) < 0)
+		return -1;
+
+	while (time(NULL) < deadline) {
+		int fd = open(node, O_RDWR | O_NOCTTY | O_NONBLOCK);
+
+		if (fd >= 0) {
+			(*opened)++;
+			close(fd);
+		}
+	}
+	unlink(node);
+	return 0;
+}
+
+/* The kernel log, since a warning fails nothing by itself. */
+static int kmsg_open(void)
+{
+	int fd = open("/dev/kmsg", O_RDONLY | O_NONBLOCK);
+
+	if (fd >= 0)
+		lseek(fd, 0, SEEK_END);
+	return fd;
+}
+
+static int kmsg_check(int fd)
+{
+	static const char * const ours[] = {
+		"tty_release", "release_tty", "check_tty_count",
+		"vtty_open_master", "vtty_shutdown",
+	};
+	char buf[8192];
+	int found = 0;
+	ssize_t r;
+	size_t i;
+
+	while (fd >= 0 && (r = read(fd, buf, sizeof(buf) - 1)) > 0) {
+		buf[r] = '\0';
+		if (!strstr(buf, "WARNING") && !strstr(buf, "BUG") &&
+		    !strstr(buf, "Oops") && !strstr(buf, "general protection"))
+			continue;
+		for (i = 0; i < ARRAY_SIZE(ours); i++)
+			if (strstr(buf, ours[i])) {
+				ksft_print_msg("kernel log: %s", buf);
+				found++;
+				break;
+			}
+	}
+	return found;
+}
+
+int main(int argc, char **argv)
+{
+	unsigned long master_opened = 0, slave_opened = 0;
+	int cg, ctid, ctl, kmsg, ready[2], count[2], status;
+	const char *env = getenv("VE_VTTY_SECS");
+	char path[PATH_MAX], val[16], c;
+	time_t deadline;
+	long secs;
+	pid_t pid;
+
+	ksft_print_header();
+	secs = argc > 1 ? atol(argv[1]) : (env ? atol(env) : DEFAULT_SECS);
+	if (secs <= 0)
+		secs = DEFAULT_SECS;
+
+	ctl = open("/dev/vzctl", O_RDWR);
+	if (ctl < 0)
+		ksft_exit_skip("cannot open /dev/vzctl: %s, the vz modules "
+			       "(vzdev, vzmon) are needed\n", strerror(errno));
+
+	cg = mount_cg2_fd();
+	if (cg < 0)
+		ksft_exit_skip("cannot mount cgroup2: %s\n", strerror(errno));
+	write_file_at(cg, "cgroup.subtree_control", VE_CONTROLLERS);
+
+	ctid = make_ve(cg, CTID_MIN);
+	if (ctid < 0)
+		ksft_exit_skip("cannot make a VE cgroup\n");
+
+	/*
+	 * The pair is filed under the veid of the VE, so the two ends only
+	 * meet if the cgroup carries the one the master is opened for.
+	 */
+	snprintf(path, sizeof(path), "%d/ve.veid", ctid);
+	snprintf(val, sizeof(val), "%d", ctid);
+	if (write_file_at(cg, path, val) < 0) {
+		destroy_ve(cg, ctid);
+		ksft_exit_skip("cannot set ve.veid: %s\n", strerror(errno));
+	}
+
+	/* Do not report a failure where the vtty pair cannot be had at all. */
+	status = open_master(ctl, ctid);
+	if (status < 0 && errno != EBUSY) {
+		destroy_ve(cg, ctid);
+		ksft_exit_skip("no vtty master: %s\n", strerror(errno));
+	}
+	if (status >= 0)
+		close(status);
+
+	ksft_set_plan(1);
+	kmsg = kmsg_open();
+	if (kmsg < 0)
+		ksft_print_msg("cannot read /dev/kmsg: %s, only a crash will "
+			       "be noticed\n", strerror(errno));
+
+	if (pipe(ready) || pipe(count))
+		ksft_exit_fail_msg("pipe: %s\n", strerror(errno));
+
+	deadline = time(NULL) + secs;
+	ksft_print_msg("VE %d, pair %d, %ld seconds\n", ctid, VTTY_IDX, secs);
+
+	pid = fork();
+	if (pid == 0) {
+		close(ready[0]);
+		close(count[0]);
+		if (enter_cgroup(cg, ctid) < 0)
+			_exit(1);
+		/*
+		 * CLONE_NEWVE puts the task in the VE the cgroup names, so
+		 * the slave lookup finds the pair.  The pid namespace is
+		 * what a VE wants of its first task.
+		 */
+		if (unshare(CLONE_NEWVE | CLONE_NEWPID | CLONE_NEWNS) < 0)
+			_exit(1);
+		if (fork() == 0) {
+			unsigned long n = 0;
+
+			c = 'r';
+			if (write(ready[1], &c, 1) != 1)
+				_exit(1);
+			if (hammer_slave(deadline, &n) < 0)
+				_exit(1);
+			if (write(count[1], &n, sizeof(n)) != sizeof(n))
+				_exit(1);
+			_exit(0);
+		}
+		wait(&status);
+		_exit(WIFEXITED(status) ? WEXITSTATUS(status) : 1);
+	}
+	close(ready[1]);
+	close(count[1]);
+
+	if (read(ready[0], &c, 1) != 1) {
+		waitpid(pid, &status, 0);
+		destroy_ve(cg, ctid);
+		ksft_exit_fail_msg("the VE side never came up\n");
+	}
+
+	while (time(NULL) < deadline) {
+		int fd = open_master(ctl, ctid);
+
+		if (fd >= 0) {
+			master_opened++;
+			close(fd);
+		}
+	}
+
+	if (read(count[0], &slave_opened, sizeof(slave_opened)) !=
+	    sizeof(slave_opened))
+		slave_opened = 0;
+	waitpid(pid, &status, 0);
+
+	ksft_print_msg("%lu master opens, %lu slave opens\n",
+		       master_opened, slave_opened);
+
+	status = kmsg_check(kmsg);
+	destroy_ve(cg, ctid);
+
+	if (!master_opened)
+		ksft_exit_fail_msg("no master was ever opened\n");
+	if (!slave_opened)
+		ksft_exit_fail_msg("no slave was ever opened\n");
+	if (status)
+		ksft_exit_fail_msg("kernel complained %d time(s)\n", status);
+
+	ksft_test_result_pass("vtty pair closed from both ends\n");
+	ksft_finished();
+}
-- 
2.55.0

_______________________________________________
Devel mailing list
Devel@openvz.org
https://lists.openvz.org/mailman/listinfo/devel

Re: [Devel] [PATCH vz10 1/2] selftests: ve: grant the directories the files sit in

[Vasileios Almpanis]

> The sysfs variant names nested leaves, kernel/vmcoreinfo and
> kernel/notes, while the proc one names files at the top of the
> filesystem. Both enforcement tests grant the leaves and nothing else,
> so in the sysfs case the lookup stops at /sys/kernel, which a fresh VE
> cannot traverse, and every open answers ENOENT:
> 
>   not ok 14 ve_perms.sysfs.enforce_allows
>   not ok 15 ve_perms.sysfs.enforce_denies
> 
> Grant x on each directory along the way, taken from the path the
> variant already gives. A file at the top of the filesystem has none
> and needs nothing, so the proc variant is unaffected.
> 
> The suite then passes 16 of 16, where it passed 14 before.
> 
> https://virtuozzo.atlassian.net/browse/VSTOR-144955
> 
> Feature: fix vz selftests
Fixes: 303ce49b7446 ("selftests/ve: add ve_perms test for proc and sysfs")

-- 
Vasileios Almpanis <vasileios.almpanis@virtuozzo.com>
_______________________________________________
Devel mailing list
Devel@openvz.org
https://lists.openvz.org/mailman/listinfo/devel

Re: [Devel] [PATCH vz10 2/2] selftests: ve: introduce vtty pair teardown stress test

[Vasileios Almpanis]

> A vtty pair is created by the first master open and torn down by the
> last close. The close racing the peer's close used to let both sides
> decide they were the final one and call release_tty() twice, and a
> master opening again while a teardown was in flight used to hand out a
> reference to a tty_struct about to be freed.
> 
> Hammer both ends. The master comes from the vzctl ioctl, which does
> not look the VE up. The slave is only reachable from inside the VE, as
> TTY_MAJOR minor 1..MAX_NR_VTTY_CONSOLES, which vtty_driver() maps to
> vttys index minor - 1, so the test builds a VE with cgroup2, sets
> ve.veid to the cgroup it made, and runs the slave side there.
> 
> One of the symtoms of a buggy kernel is dmesg warning, not just an
> eventual crash, so the test checks that. A crashed node should also
> report test failure in CI, but that's less verbose, hence the check.
> 
> https://virtuozzo.atlassian.net/browse/VSTOR-144771
> 
> Feature: ve selftest
> Signed-off-by: Eva Kurchatova <eva.kurchatova@virtuozzo.com>
>
> diff --git a/tools/testing/selftests/ve/Makefile b/tools/testing/selftests/ve/Makefile
> index ec40cbc7b3a1..6cd5823c4d93 100644
> --- a/tools/testing/selftests/ve/Makefile
> +++ b/tools/testing/selftests/ve/Makefile
> @@ -4,5 +4,6 @@ CFLAGS += -g -Wall -O2
>  
>  TEST_GEN_PROGS += ve_ns_owner_test
>  TEST_GEN_PROGS += ve_perms_test
> +TEST_GEN_PROGS += ve_vtty_stress

Please add to .gitignore too

>  
>  include ../lib.mk
> diff --git a/tools/testing/selftests/ve/settings b/tools/testing/selftests/ve/settings
> new file mode 100644
> index 000000000000..e2206265f67c
> --- /dev/null
> +++ b/tools/testing/selftests/ve/settings
> @@ -0,0 +1 @@
> +timeout=900
> diff --git a/tools/testing/selftests/ve/ve_vtty_stress.c b/tools/testing/selftests/ve/ve_vtty_stress.c
> new file mode 100644
> index 000000000000..9037f731c58d
> --- /dev/null
> +++ b/tools/testing/selftests/ve/ve_vtty_stress.c
> @@ -0,0 +1,244 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * ve_vtty_stress - close a vtty pair from both ends at once.
> + *
> + * A vtty pair is created by the first master open and torn down by the
> + * last close.  A close racing the peer's close used to let both sides
> + * decide they were the final one and call release_tty() twice, and a
> + * master opened again while a teardown was still in flight used to hand
> + * out a reference to a tty_struct that was about to be freed.  Either
> + * way the next close walked freed memory.
> + *
> + * The master comes from the vzctl ioctl, which does not look the VE up.
> + * The slave is only reachable from inside the VE, as TTY_MAJOR minor
> + * 1..MAX_NR_VTTY_CONSOLES, which vtty_driver() maps to vttys index
> + * minor - 1.  So the test makes a VE with cgroup2, hammers the master
> + * from the host and the slave from a task inside it, and fails if the
> + * kernel logs a complaint about the teardown.
> + *
> + * Surviving is not a pass on its own: the first symptom is a warning,
> + * which stops nothing by itself.
> + *
> + * Usage: ve_vtty_stress [seconds]   (default 600, or $VE_VTTY_SECS)
> + */
> +#define _GNU_SOURCE
> +#include <sched.h>
> +#include <stdbool.h>
> +#include <sys/ioctl.h>
> +#include <linux/major.h>
> +#include <sys/sysmacros.h>
> +#include <sys/wait.h>
> +#include <time.h>
> +
> +#include "ve_selftest.h"
> +#include "../kselftest.h"
> +
> +/* The ioctl argument; the trailing data[] the uapi struct has is unused. */
> +struct vzctl_ve_configure {
> +	unsigned int veid, key, val, size;
> +};
> +
> +#define VZCTL_VE_CONFIGURE	_IOW('.', 15, struct vzctl_ve_configure)
> +#define VE_CONFIGURE_OPEN_TTY	5
> +
> +#define VTTY_IDX	0		/* the pair both ends work on */
> +#define SLAVE_MINOR	(VTTY_IDX + 1)	/* vtty_driver(): index = minor - 1 */
> +#define DEFAULT_SECS	600
> +
> +static int open_master(int ctl_fd, unsigned int veid)
> +{
> +	struct vzctl_ve_configure c = {
> +		.veid = veid, .key = VE_CONFIGURE_OPEN_TTY, .val = VTTY_IDX,
> +	};
> +
> +	return ioctl(ctl_fd, VZCTL_VE_CONFIGURE, &c);
> +}
> +
> +/*
> + * The slave end, inside the VE.  Every error here is one the race is
> + * expected to produce: the pair is gone once the master has closed it.
> + */
> +static int hammer_slave(time_t deadline, unsigned long *opened)
> +{
> +	char node[] = "/tmp/ve_vtty_slave";
> +
> +	unlink(node);
> +	if (mknod(node, S_IFCHR | 0600, makedev(TTY_MAJOR, SLAVE_MINOR)) < 0)
> +		return -1;
> +
> +	while (time(NULL) < deadline) {
> +		int fd = open(node, O_RDWR | O_NOCTTY | O_NONBLOCK);
> +
> +		if (fd >= 0) {
> +			(*opened)++;
> +			close(fd);
> +		}
> +	}
> +	unlink(node);
> +	return 0;
> +}
> +
> +/* The kernel log, since a warning fails nothing by itself. */
> +static int kmsg_open(void)
> +{
> +	int fd = open("/dev/kmsg", O_RDONLY | O_NONBLOCK);
> +
> +	if (fd >= 0)
> +		lseek(fd, 0, SEEK_END);
> +	return fd;
> +}
> +
> +static int kmsg_check(int fd)
> +{
> +	static const char * const ours[] = {
> +		"tty_release", "release_tty", "check_tty_count",
> +		"vtty_open_master", "vtty_shutdown",
> +	};
> +	char buf[8192];
> +	int found = 0;
> +	ssize_t r;
> +	size_t i;
> +
> +	while (fd >= 0 && (r = read(fd, buf, sizeof(buf) - 1)) > 0) {
> +		buf[r] = '\0';
> +		if (!strstr(buf, "WARNING") && !strstr(buf, "BUG") &&
> +		    !strstr(buf, "Oops") && !strstr(buf, "general protection"))
> +			continue;
> +		for (i = 0; i < ARRAY_SIZE(ours); i++)
> +			if (strstr(buf, ours[i])) {
> +				ksft_print_msg("kernel log: %s", buf);
> +				found++;
> +				break;
> +			}
> +	}
> +	return found;
> +}
> +
> +int main(int argc, char **argv)
> +{
> +	unsigned long master_opened = 0, slave_opened = 0;
> +	int cg, ctid, ctl, kmsg, ready[2], count[2], status;
> +	const char *env = getenv("VE_VTTY_SECS");
> +	char path[PATH_MAX], val[16], c;
> +	time_t deadline;
> +	long secs;
> +	pid_t pid;
> +
> +	ksft_print_header();
> +	secs = argc > 1 ? atol(argv[1]) : (env ? atol(env) : DEFAULT_SECS);
> +	if (secs <= 0)
> +		secs = DEFAULT_SECS;
> +
> +	ctl = open("/dev/vzctl", O_RDWR);
> +	if (ctl < 0)
> +		ksft_exit_skip("cannot open /dev/vzctl: %s, the vz modules "
> +			       "(vzdev, vzmon) are needed\n", strerror(errno));
> +
> +	cg = mount_cg2_fd();
> +	if (cg < 0)
> +		ksft_exit_skip("cannot mount cgroup2: %s\n", strerror(errno));
> +	write_file_at(cg, "cgroup.subtree_control", VE_CONTROLLERS);
> +
> +	ctid = make_ve(cg, CTID_MIN);
> +	if (ctid < 0)
> +		ksft_exit_skip("cannot make a VE cgroup\n");
> +
> +	/*
> +	 * The pair is filed under the veid of the VE, so the two ends only
> +	 * meet if the cgroup carries the one the master is opened for.
> +	 */
> +	snprintf(path, sizeof(path), "%d/ve.veid", ctid);
> +	snprintf(val, sizeof(val), "%d", ctid);
> +	if (write_file_at(cg, path, val) < 0) {
> +		destroy_ve(cg, ctid);
> +		ksft_exit_skip("cannot set ve.veid: %s\n", strerror(errno));
> +	}
> +
> +	/* Do not report a failure where the vtty pair cannot be had at all. */
> +	status = open_master(ctl, ctid);
> +	if (status < 0 && errno != EBUSY) {
> +		destroy_ve(cg, ctid);
> +		ksft_exit_skip("no vtty master: %s\n", strerror(errno));
> +	}
> +	if (status >= 0)
> +		close(status);
> +
> +	ksft_set_plan(1);
> +	kmsg = kmsg_open();
> +	if (kmsg < 0)
> +		ksft_print_msg("cannot read /dev/kmsg: %s, only a crash will "
> +			       "be noticed\n", strerror(errno));
> +
> +	if (pipe(ready) || pipe(count))
> +		ksft_exit_fail_msg("pipe: %s\n", strerror(errno));
> +
> +	deadline = time(NULL) + secs;
> +	ksft_print_msg("VE %d, pair %d, %ld seconds\n", ctid, VTTY_IDX, secs);
> +
> +	pid = fork();

Fork could also return error. Please handle it.

-- 
Vasileios Almpanis <vasileios.almpanis@virtuozzo.com>
_______________________________________________
Devel mailing list
Devel@openvz.org
https://lists.openvz.org/mailman/listinfo/devel