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* [PATCH 1/2] futex: adjust a futex timeout with a per-timens offset
@ 2020-10-15  7:29 Andrei Vagin
  2020-10-15  7:29 ` [PATCH 2/2] selftests/timens: Add a test for futex() Andrei Vagin
                   ` (2 more replies)
  0 siblings, 3 replies; 8+ messages in thread
From: Andrei Vagin @ 2020-10-15  7:29 UTC (permalink / raw)
  To: Thomas Gleixner, linux-kernel
  Cc: Ingo Molnar, Peter Zijlstra, Darren Hart, Dmitry Safonov,
	Shuah Khan, Andrei Vagin, stable

For all commands except FUTEX_WAIT, timeout is interpreted as an
absolute value. This absolute value is inside the task's time namespace
and has to be converted to the host's time.

Cc: <stable@vger.kernel.org>
Fixes: 5a590f35add9 ("posix-clocks: Wire up clock_gettime() with timens offsets")
Reported-by: Hans van der Laan <j.h.vanderlaan@student.utwente.nl>
Signed-off-by: Andrei Vagin <avagin@gmail.com>
---
 kernel/futex.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/kernel/futex.c b/kernel/futex.c
index a5876694a60e..9ff2b8c5a506 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -39,6 +39,7 @@
 #include <linux/freezer.h>
 #include <linux/memblock.h>
 #include <linux/fault-inject.h>
+#include <linux/time_namespace.h>
 
 #include <asm/futex.h>
 
@@ -3797,6 +3798,8 @@ SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, u32, val,
 		t = timespec64_to_ktime(ts);
 		if (cmd == FUTEX_WAIT)
 			t = ktime_add_safe(ktime_get(), t);
+		else if (!(cmd & FUTEX_CLOCK_REALTIME))
+			t = timens_ktime_to_host(CLOCK_MONOTONIC, t);
 		tp = &t;
 	}
 	/*
-- 
2.26.2


^ permalink raw reply related	[flat|nested] 8+ messages in thread
* [PATCH 2/2 v2] selftests/timens: Add a test for futex()
@ 2020-10-15 16:00 Andrei Vagin
  2020-10-20 15:11 ` [tip: timers/urgent] " tip-bot2 for Andrei Vagin
  0 siblings, 1 reply; 8+ messages in thread
From: Andrei Vagin @ 2020-10-15 16:00 UTC (permalink / raw)
  To: Thomas Gleixner, linux-kernel
  Cc: Ingo Molnar, Peter Zijlstra, Darren Hart, Dmitry Safonov,
	Shuah Khan, Andrei Vagin

Output on success:
 1..2
 ok 1 futex with the 0 clockid
 ok 2 futex with the 1 clockid
 # Totals: pass:2 fail:0 xfail:0 xpass:0 skip:0 error:0

Signed-off-by: Andrei Vagin <avagin@gmail.com>
---
v2: extend the test to check FUTEX_CLOCK_REALTIME

 tools/testing/selftests/timens/Makefile |   2 +-
 tools/testing/selftests/timens/futex.c  | 110 ++++++++++++++++++++++++
 2 files changed, 111 insertions(+), 1 deletion(-)
 create mode 100644 tools/testing/selftests/timens/futex.c

diff --git a/tools/testing/selftests/timens/Makefile b/tools/testing/selftests/timens/Makefile
index b4fd9a934654..3a5936cc10ab 100644
--- a/tools/testing/selftests/timens/Makefile
+++ b/tools/testing/selftests/timens/Makefile
@@ -1,4 +1,4 @@
-TEST_GEN_PROGS := timens timerfd timer clock_nanosleep procfs exec
+TEST_GEN_PROGS := timens timerfd timer clock_nanosleep procfs exec futex
 TEST_GEN_PROGS_EXTENDED := gettime_perf
 
 CFLAGS := -Wall -Werror -pthread
diff --git a/tools/testing/selftests/timens/futex.c b/tools/testing/selftests/timens/futex.c
new file mode 100644
index 000000000000..6b2b9264e851
--- /dev/null
+++ b/tools/testing/selftests/timens/futex.c
@@ -0,0 +1,110 @@
+// SPDX-License-Identifier: GPL-2.0
+#define _GNU_SOURCE
+#include <sched.h>
+
+#include <linux/unistd.h>
+#include <linux/futex.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/syscall.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <time.h>
+#include <unistd.h>
+
+#include "log.h"
+#include "timens.h"
+
+#define NSEC_PER_SEC 1000000000ULL
+
+static int run_test(int clockid)
+{
+	int futex_op = FUTEX_WAIT_BITSET;
+	struct timespec timeout, end;
+	int val = 0;
+
+	if (clockid == CLOCK_REALTIME)
+		futex_op |= FUTEX_CLOCK_REALTIME;
+
+	clock_gettime(clockid, &timeout);
+	timeout.tv_nsec += NSEC_PER_SEC / 10; // 100ms
+	if (timeout.tv_nsec > NSEC_PER_SEC) {
+		timeout.tv_sec++;
+		timeout.tv_nsec -= NSEC_PER_SEC;
+	}
+
+	if (syscall(__NR_futex, &val, futex_op, 0,
+		    &timeout, 0, FUTEX_BITSET_MATCH_ANY) >= 0) {
+		ksft_test_result_fail("futex didn't return ETIMEDOUT\n");
+		return 1;
+	}
+
+	if (errno != ETIMEDOUT) {
+		ksft_test_result_fail("futex didn't return ETIMEDOUT: %s\n",
+							strerror(errno));
+		return 1;
+	}
+
+	clock_gettime(clockid, &end);
+
+	if (end.tv_sec < timeout.tv_sec ||
+	    (end.tv_sec == timeout.tv_sec && end.tv_nsec < timeout.tv_nsec)) {
+		ksft_test_result_fail("futex slept less than 100ms\n");
+		return 1;
+	}
+
+
+	ksft_test_result_pass("futex with the %d clockid\n", clockid);
+
+	return 0;
+}
+
+int main(int argc, char *argv[])
+{
+	int status, len, fd;
+	char buf[4096];
+	pid_t pid;
+	struct timespec mtime_now;
+
+	nscheck();
+
+	ksft_set_plan(2);
+
+	clock_gettime(CLOCK_MONOTONIC, &mtime_now);
+
+	if (unshare_timens())
+		return 1;
+
+	len = snprintf(buf, sizeof(buf), "%d %d 0",
+			CLOCK_MONOTONIC, 70 * 24 * 3600);
+	fd = open("/proc/self/timens_offsets", O_WRONLY);
+	if (fd < 0)
+		return pr_perror("/proc/self/timens_offsets");
+
+	if (write(fd, buf, len) != len)
+		return pr_perror("/proc/self/timens_offsets");
+
+	close(fd);
+
+	pid = fork();
+	if (pid < 0)
+		return pr_perror("Unable to fork");
+	if (pid == 0) {
+		int ret = 0;
+
+		ret |= run_test(CLOCK_REALTIME);
+		ret |= run_test(CLOCK_MONOTONIC);
+		if (ret)
+			ksft_exit_fail();
+		ksft_exit_pass();
+		return 0;
+	}
+
+	if (waitpid(pid, &status, 0) != pid)
+		return pr_perror("Unable to wait the child process");
+
+	if (WIFEXITED(status))
+		return WEXITSTATUS(status);
+
+	return 1;
+}
-- 
2.26.2


^ permalink raw reply related	[flat|nested] 8+ messages in thread
end of thread, other threads:[~2020-10-20 15:11 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-10-15  7:29 [PATCH 1/2] futex: adjust a futex timeout with a per-timens offset Andrei Vagin
2020-10-15  7:29 ` [PATCH 2/2] selftests/timens: Add a test for futex() Andrei Vagin
2020-10-15  9:35   ` [tip: timers/urgent] " tip-bot2 for Andrei Vagin
2020-10-15  9:35 ` [tip: timers/urgent] futex: Adjust futex absolute timeouts with per-timens offset tip-bot2 for Andrei Vagin
2020-10-15 13:26 ` [PATCH 1/2] futex: adjust a futex timeout with a " Dmitry Safonov
2020-10-15 14:13   ` Thomas Gleixner
2020-10-16  8:18     ` Andrei Vagin
2020-10-15 16:00 [PATCH 2/2 v2] selftests/timens: Add a test for futex() Andrei Vagin
2020-10-20 15:11 ` [tip: timers/urgent] " tip-bot2 for Andrei Vagin

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