From c2f7d08cccf4af2ce6992feaabb9e68e4ae0bff3 Mon Sep 17 00:00:00 2001 From: Andrei Vagin Date: Thu, 15 Oct 2020 09:00:19 -0700 Subject: futex: Adjust absolute futex timeouts with per time namespace offset For all commands except FUTEX_WAIT, the 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. Fixes: 5a590f35add9 ("posix-clocks: Wire up clock_gettime() with timens offsets") Reported-by: Hans van der Laan Signed-off-by: Andrei Vagin Signed-off-by: Thomas Gleixner Reviewed-by: Dmitry Safonov <0x7f454c46@gmail.com> Cc: Link: https://lore.kernel.org/r/20201015160020.293748-1-avagin@gmail.com --- kernel/futex.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/kernel/futex.c b/kernel/futex.c index 680854dcf156..be68ac0d49ad 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -39,6 +39,7 @@ #include #include #include +#include #include @@ -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 (!(op & FUTEX_CLOCK_REALTIME)) + t = timens_ktime_to_host(CLOCK_MONOTONIC, t); tp = &t; } /* @@ -3989,6 +3992,8 @@ SYSCALL_DEFINE6(futex_time32, 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 (!(op & FUTEX_CLOCK_REALTIME)) + t = timens_ktime_to_host(CLOCK_MONOTONIC, t); tp = &t; } if (cmd == FUTEX_REQUEUE || cmd == FUTEX_CMP_REQUEUE || -- cgit From a4fd8414659bf470e2146b352574bbd274e54b7a Mon Sep 17 00:00:00 2001 From: Andrei Vagin Date: Thu, 15 Oct 2020 09:00:20 -0700 Subject: selftests/timens: Add a test for futex() 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 Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20201015160020.293748-2-avagin@gmail.com --- 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 + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#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; +} -- cgit