From mboxrd@z Thu Jan 1 00:00:00 1970 From: Li Wang Date: Mon, 23 Nov 2020 08:31:36 +0000 Subject: [LTP] [PATCH 1/2] syscalls: avoid time() using __cvdso_gettimeofday in use-level's VDSO Message-ID: <20201123083137.11575-1-liwang@redhat.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: ltp@lists.linux.it This shmctl01 test detect the time as the number of seconds twice (before and after) the shmget() instruction, then it verifies whether the 'struct shmid_ds ds' gets data correctly. But here it shows 'ds->ctime' out of the seconds range (1604298586, 1604298586), The reason is that shmget()/msgsnd() always use ktime_get_real_second to get real seconds, but time() on aarch64 via gettimeofday() or (it depends on different kernel versions) clock_gettime() in use-level's VDSO to return tv_sec. time() __cvdso_gettimeofday ... do_gettimeofday ktime_get_real_ts64 timespc64_add_ns Situation can be simplify as difference between ktime_get_real_second and ktime_get_real_ts64. As we can see ktime_get_real_second return tk->xtime_sec directly, however timespc64_add_ns more easily add 1 more second via "a->tv_sec +=..." on a virtual machine, that's why we got occasional errors like: shmctl01.c:183: TFAIL: SHM_STAT: shm_ctime=1604298585, expected <1604298586,1604298586> ... msgsnd01.c:59: TFAIL: msg_stime = 1605730573 out of [1605730574, 1605730574] Here we propose to use '__NR_time' to invoke syscall directly that makes test all get real seconds via ktime_get_real_second. Signed-off-by: Li Wang Cc: Chunyu Hu Cc: Cyril Hrubis --- testcases/kernel/syscalls/ipc/msgrcv/msgrcv01.c | 5 +++-- testcases/kernel/syscalls/ipc/msgsnd/msgsnd01.c | 5 +++-- testcases/kernel/syscalls/ipc/shmctl/shmctl01.c | 5 +++-- 3 files changed, 9 insertions(+), 6 deletions(-) diff --git a/testcases/kernel/syscalls/ipc/msgrcv/msgrcv01.c b/testcases/kernel/syscalls/ipc/msgrcv/msgrcv01.c index 5c1e317e9..6fdc47dc3 100644 --- a/testcases/kernel/syscalls/ipc/msgrcv/msgrcv01.c +++ b/testcases/kernel/syscalls/ipc/msgrcv/msgrcv01.c @@ -10,6 +10,7 @@ #include "tst_test.h" #include "tst_safe_sysv_ipc.h" #include "libnewipc.h" +#include "tst_timer.h" static key_t msgkey; static int queue_id = -1, pid; @@ -25,13 +26,13 @@ static void verify_msgrcv(void) SAFE_MSGSND(queue_id, &snd_buf, MSGSIZE, 0); - time(&before_rcv); + tst_syscall(__NR_time, &before_rcv); TEST(msgrcv(queue_id, &rcv_buf, MSGSIZE, 1, 0)); if (TST_RET == -1) { tst_res(TFAIL | TTERRNO, "msgrcv failed"); return; } - time(&after_rcv); + tst_syscall(__NR_time, &after_rcv); if (strcmp(rcv_buf.mtext, snd_buf.mtext) == 0) tst_res(TPASS, "message received(%s) = message sent(%s)", diff --git a/testcases/kernel/syscalls/ipc/msgsnd/msgsnd01.c b/testcases/kernel/syscalls/ipc/msgsnd/msgsnd01.c index 5f5da52d2..9101f2668 100644 --- a/testcases/kernel/syscalls/ipc/msgsnd/msgsnd01.c +++ b/testcases/kernel/syscalls/ipc/msgsnd/msgsnd01.c @@ -16,6 +16,7 @@ #include "tst_test.h" #include "tst_safe_sysv_ipc.h" #include "libnewipc.h" +#include "tst_timer.h" static key_t msgkey; static int queue_id = -1, pid; @@ -29,13 +30,13 @@ static void verify_msgsnd(void) struct msqid_ds qs_buf; time_t before_snd, after_snd; - time(&before_snd); + tst_syscall(__NR_time, &before_snd); TEST(msgsnd(queue_id, &snd_buf, MSGSIZE, 0)); if (TST_RET == -1) { tst_res(TFAIL | TTERRNO, "msgsnd() failed"); return; } - time(&after_snd); + tst_syscall(__NR_time, &after_snd); SAFE_MSGCTL(queue_id, IPC_STAT, &qs_buf); diff --git a/testcases/kernel/syscalls/ipc/shmctl/shmctl01.c b/testcases/kernel/syscalls/ipc/shmctl/shmctl01.c index 3a39a4d74..f5b8eaef9 100644 --- a/testcases/kernel/syscalls/ipc/shmctl/shmctl01.c +++ b/testcases/kernel/syscalls/ipc/shmctl/shmctl01.c @@ -19,6 +19,7 @@ #include "tst_test.h" #include "tst_safe_sysv_ipc.h" #include "libnewipc.h" +#include "tst_timer.h" #define NCHILD 20 @@ -240,9 +241,9 @@ static int get_shm_idx_from_id(int shm_id) static void setup(void) { - ctime_min = time(NULL); + ctime_min = tst_syscall(__NR_time, NULL); shm_id = SAFE_SHMGET(IPC_PRIVATE, SHM_SIZE, IPC_CREAT | SHM_RW); - ctime_max = time(NULL); + ctime_max = tst_syscall(__NR_time, NULL); shm_idx = get_shm_idx_from_id(shm_id); -- 2.21.1