[LTP] [PATCH V4 2/2] syscalls/clock_gettime: Add test to check bug during successive readings
Viresh Kumar
viresh.kumar@linaro.org
Fri Jun 26 06:52:08 CEST 2020
An issue was reported recently where a bug was found during successive
reading of 64 bit time on arm32 platforms. Add a test for that.
https://github.com/richfelker/musl-cross-make/issues/96
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
V4: Moved some code to vdso_helpers.c
include/parse_vdso.h | 6 +
libs/libltpvdso/vdso_helpers.c | 69 ++++++++
runtest/syscalls | 1 +
.../kernel/syscalls/clock_gettime/.gitignore | 1 +
.../kernel/syscalls/clock_gettime/Makefile | 3 +
.../syscalls/clock_gettime/clock_gettime04.c | 162 ++++++++++++++++++
6 files changed, 242 insertions(+)
create mode 100644 libs/libltpvdso/vdso_helpers.c
create mode 100644 testcases/kernel/syscalls/clock_gettime/clock_gettime04.c
diff --git a/include/parse_vdso.h b/include/parse_vdso.h
index 87f5ea4fc3e8..5212fc659e34 100644
--- a/include/parse_vdso.h
+++ b/include/parse_vdso.h
@@ -28,8 +28,14 @@
*
* These are the prototypes:
*/
+
+#include <time.h>
+
extern void vdso_init_from_auxv(void *auxv);
extern void vdso_init_from_sysinfo_ehdr(uintptr_t base);
extern void *vdso_sym(const char *version, const char *name);
+typedef int (*gettime_t)(clockid_t clk_id, void *ts);
+void find_clock_gettime_vdso(gettime_t *ptr_vdso_gettime,
+ gettime_t *ptr_vdso_gettime64);
#endif /* PARSE_VDSO_H__ */
diff --git a/libs/libltpvdso/vdso_helpers.c b/libs/libltpvdso/vdso_helpers.c
new file mode 100644
index 000000000000..e958403453e0
--- /dev/null
+++ b/libs/libltpvdso/vdso_helpers.c
@@ -0,0 +1,69 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2020 Linaro Limited. All rights reserved.
+ * Author: Viresh Kumar<viresh.kumar@linaro.org>
+ */
+
+#define TST_NO_DEFAULT_MAIN
+#include "tst_test.h"
+
+#include "parse_vdso.h"
+#include <sys/auxv.h>
+
+static unsigned long sysinfo_ehdr;
+
+static void vdso_init(void)
+{
+ if (sysinfo_ehdr)
+ return;
+
+ sysinfo_ehdr = getauxval(AT_SYSINFO_EHDR);
+ if (!sysinfo_ehdr) {
+ tst_res(TINFO, "Couldn't find AT_SYSINFO_EHDR");
+ return;
+ }
+
+ vdso_init_from_sysinfo_ehdr(sysinfo_ehdr);
+}
+
+void find_clock_gettime_vdso(gettime_t *ptr_vdso_gettime,
+ gettime_t *ptr_vdso_gettime64)
+{
+ /*
+ * Some vDSO exports its clock_gettime() implementation with a different
+ * name and version from other architectures, so we need to handle it as
+ * a special case.
+ */
+#if defined(__powerpc__) || defined(__powerpc64__)
+ const char *version = "LINUX_2.6.15";
+ const char *name = "__kernel_clock_gettime";
+#elif defined(__aarch64__)
+ const char *version = "LINUX_2.6.39";
+ const char *name = "__kernel_clock_gettime";
+#elif defined(__s390__)
+ const char *version = "LINUX_2.6.29";
+ const char *name = "__kernel_clock_gettime";
+#elif defined(__nds32__)
+ const char *version = "LINUX_4";
+ const char *name = "__vdso_clock_gettime";
+#elif defined(__riscv)
+ const char *version = "LINUX_4.15";
+ const char *name = "__vdso_clock_gettime";
+#else
+ const char *version = "LINUX_2.6";
+ const char *name = "__vdso_clock_gettime";
+#endif
+
+ const char *version64 = "LINUX_2.6";
+ const char *name64 = "__vdso_clock_gettime64";
+
+ vdso_init();
+
+ *ptr_vdso_gettime = vdso_sym(version, name);
+ if (!*ptr_vdso_gettime)
+ tst_res(TINFO, "Couldn't find vdso_gettime()");
+
+ *ptr_vdso_gettime64 = vdso_sym(version64, name64);
+ if (!*ptr_vdso_gettime64)
+ tst_res(TINFO, "Couldn't find vdso_gettime64()");
+}
diff --git a/runtest/syscalls b/runtest/syscalls
index f245529f868d..718ac1148392 100644
--- a/runtest/syscalls
+++ b/runtest/syscalls
@@ -96,6 +96,7 @@ clock_nanosleep04 clock_nanosleep04
clock_gettime01 clock_gettime01
clock_gettime02 clock_gettime02
clock_gettime03 clock_gettime03
+clock_gettime04 clock_gettime04
leapsec01 leapsec01
clock_settime01 clock_settime01
diff --git a/testcases/kernel/syscalls/clock_gettime/.gitignore b/testcases/kernel/syscalls/clock_gettime/.gitignore
index 9d06613b6f41..304eedab68c6 100644
--- a/testcases/kernel/syscalls/clock_gettime/.gitignore
+++ b/testcases/kernel/syscalls/clock_gettime/.gitignore
@@ -1,4 +1,5 @@
clock_gettime01
clock_gettime02
clock_gettime03
+clock_gettime04
leapsec01
diff --git a/testcases/kernel/syscalls/clock_gettime/Makefile b/testcases/kernel/syscalls/clock_gettime/Makefile
index e49cb9b357a4..1c1cbd7a8853 100644
--- a/testcases/kernel/syscalls/clock_gettime/Makefile
+++ b/testcases/kernel/syscalls/clock_gettime/Makefile
@@ -3,8 +3,11 @@
top_srcdir ?= ../../../..
+LTPLIBS = ltpvdso
+
include $(top_srcdir)/include/mk/testcases.mk
LDLIBS+=-lrt
+clock_gettime04: LDLIBS += -lltpvdso
include $(top_srcdir)/include/mk/generic_leaf_target.mk
diff --git a/testcases/kernel/syscalls/clock_gettime/clock_gettime04.c b/testcases/kernel/syscalls/clock_gettime/clock_gettime04.c
new file mode 100644
index 000000000000..97b6ea7ddcd3
--- /dev/null
+++ b/testcases/kernel/syscalls/clock_gettime/clock_gettime04.c
@@ -0,0 +1,162 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2020 Linaro Limited. All rights reserved.
+ * Author: Viresh Kumar<viresh.kumar@linaro.org>
+ *
+ * Check time difference between successive readings and report a bug if
+ * difference found to be over 5 ms.
+ */
+
+#include "config.h"
+#include "parse_vdso.h"
+#include "tst_timer.h"
+#include "tst_safe_clocks.h"
+
+clockid_t clks[] = {
+ CLOCK_REALTIME,
+ CLOCK_REALTIME_COARSE,
+ CLOCK_MONOTONIC,
+ CLOCK_MONOTONIC_COARSE,
+ CLOCK_MONOTONIC_RAW,
+ CLOCK_BOOTTIME,
+};
+
+static gettime_t ptr_vdso_gettime, ptr_vdso_gettime64;
+
+static inline int _vdso_gettime(gettime_t vdso, clockid_t clk_id, void *ts)
+{
+ if (!vdso) {
+ errno = ENOSYS;
+ return -1;
+ }
+
+ return vdso(clk_id, ts);
+}
+
+static inline int vdso_gettime(clockid_t clk_id, void *ts)
+{
+ return _vdso_gettime(ptr_vdso_gettime, clk_id, ts);
+}
+
+static inline int vdso_gettime64(clockid_t clk_id, void *ts)
+{
+ return _vdso_gettime(ptr_vdso_gettime64, clk_id, ts);
+}
+
+static inline int my_gettimeofday(clockid_t clk_id, void *ts)
+{
+ struct timeval tval;
+
+ if (clk_id != CLOCK_REALTIME)
+ tst_brk(TBROK, "%s: Invalid clk_id, exiting", tst_clock_name(clk_id));
+
+ if (gettimeofday(&tval, NULL) < 0)
+ tst_brk(TBROK | TERRNO, "gettimeofday() failed");
+
+ /*
+ * The array defines the type to TST_LIBC_TIMESPEC and so we can cast
+ * this into struct timespec.
+ */
+ *((struct timespec *)ts) = tst_timespec_from_us(tst_timeval_to_us(tval));
+ return 0;
+}
+
+static struct test_variants {
+ int (*gettime)(clockid_t clk_id, void *ts);
+ enum tst_ts_type type;
+ char *desc;
+} variants[] = {
+ { .gettime = libc_clock_gettime, .type = TST_LIBC_TIMESPEC, .desc = "vDSO or syscall with libc spec"},
+
+#if (__NR_clock_gettime != __LTP__NR_INVALID_SYSCALL)
+ { .gettime = sys_clock_gettime, .type = TST_KERN_OLD_TIMESPEC, .desc = "syscall with old kernel spec"},
+ { .gettime = vdso_gettime, .type = TST_KERN_OLD_TIMESPEC, .desc = "vDSO with old kernel spec"},
+#endif
+
+#if (__NR_clock_gettime64 != __LTP__NR_INVALID_SYSCALL)
+ { .gettime = sys_clock_gettime64, .type = TST_KERN_TIMESPEC, .desc = "syscall time64 with kernel spec"},
+ { .gettime = vdso_gettime64, .type = TST_KERN_TIMESPEC, .desc = "vDSO time64 with kernel spec"},
+#endif
+ { .gettime = my_gettimeofday, .type = TST_LIBC_TIMESPEC, .desc = "gettimeofday"},
+};
+
+static void setup(void)
+{
+ find_clock_gettime_vdso(&ptr_vdso_gettime, &ptr_vdso_gettime64);
+}
+
+static void run(unsigned int i)
+{
+ struct tst_ts ts;
+ long long start, end = 0, diff, slack;
+ struct test_variants *tv;
+ int count = 10000, ret;
+ unsigned int j;
+
+ do {
+ for (j = 0; j < ARRAY_SIZE(variants); j++) {
+ /* Refresh time in start */
+ start = end;
+
+ tv = &variants[j];
+ ts.type = tv->type;
+
+ /* Do gettimeofday() test only for CLOCK_REALTIME */
+ if (tv->gettime == my_gettimeofday && clks[i] != CLOCK_REALTIME)
+ continue;
+
+ ret = tv->gettime(clks[i], tst_ts_get(&ts));
+ if (ret) {
+ /*
+ * _vdso_gettime() sets error to ENOSYS if vdso
+ * isn't available.
+ */
+ if (errno == ENOSYS)
+ continue;
+
+ tst_res(TFAIL | TERRNO, "%s: clock_gettime() failed (%d)",
+ tst_clock_name(clks[i]), j);
+ return;
+ }
+
+ end = tst_ts_to_ns(ts);
+
+ /* Skip comparison on first traversal */
+ if (count == 10000 && !j)
+ continue;
+
+ /*
+ * gettimeofday() doesn't capture time less than 1 us,
+ * add 999 to it.
+ */
+ if (tv->gettime == my_gettimeofday)
+ slack = 999;
+ else
+ slack = 0;
+
+ diff = end + slack - start;
+ if (diff < 0) {
+ tst_res(TFAIL, "%s: Time travelled backwards (%d): %lld ns",
+ tst_clock_name(clks[i]), j, diff);
+ return;
+ }
+
+ diff /= 1000000;
+
+ if (diff >= 5) {
+ tst_res(TFAIL, "%s: Difference between successive readings greater than 5 ms (%d): %lld",
+ tst_clock_name(clks[i]), j, diff);
+ return;
+ }
+ }
+ } while (--count);
+
+ tst_res(TPASS, "%s: Difference between successive readings is reasonable",
+ tst_clock_name(clks[i]));
+}
+
+static struct tst_test test = {
+ .test = run,
+ .setup = setup,
+ .tcnt = ARRAY_SIZE(clks),
+};
--
2.25.0.rc1.19.g042ed3e048af
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