| From e747d0456adc080a1d31fb653bda9dc491795c80 Mon Sep 17 00:00:00 2001 |
| From: Jan Stancek <jstancek@redhat.com> |
| Date: Sun, 16 Jun 2019 11:14:16 +0200 |
| Subject: [PATCH] syscalls/tgkill03: wait for defunct tid to get detached |
| |
| Case where defunct tid is used has been observed to sporadically fail: |
| tgkill03.c:96: FAIL: Defunct tid should have failed with ESRCH: SUCCESS |
| |
| glibc __pthread_timedjoin_ex() waits for CLONE_CHILD_CLEARTID to clear tid, |
| and then resumes. Kernel clears it (glibc pd->tid) at: |
| do_exit |
| exit_mm |
| mm_release |
| put_user(0, tsk->clear_child_tid); |
| |
| but kernel tid is still valid, presumably until: |
| release_task |
| __exit_signal |
| __unhash_process |
| detach_pid |
| |
| To avoid race wait until /proc/<pid>/task/<tid> disappears. |
| |
| Signed-off-by: Jan Stancek <jstancek@redhat.com> |
| Reviewed-by: Li Wang <liwang@redhat.com> |
| Acked-by: Sumit Garg <sumit.garg@linaro.org> |
| |
| Upstream-Status: Backport |
| [https://github.com/linux-test-project/ltp/commit/e747d0456adc080a1d31fb653bda9dc491795c80] |
| |
| Signed-off-by: He Zhe <zhe.he@windriver.com> |
| --- |
| testcases/kernel/syscalls/tgkill/tgkill03.c | 6 +++++- |
| 1 file changed, 5 insertions(+), 1 deletion(-) |
| |
| diff --git a/testcases/kernel/syscalls/tgkill/tgkill03.c b/testcases/kernel/syscalls/tgkill/tgkill03.c |
| index f5bbdc5..593a217 100644 |
| --- a/testcases/kernel/syscalls/tgkill/tgkill03.c |
| +++ b/testcases/kernel/syscalls/tgkill/tgkill03.c |
| @@ -7,6 +7,7 @@ |
| |
| #include <pthread.h> |
| #include <pwd.h> |
| +#include <stdio.h> |
| #include <sys/types.h> |
| |
| #include "tst_safe_pthread.h" |
| @@ -42,6 +43,7 @@ static void setup(void) |
| { |
| sigset_t sigusr1; |
| pthread_t defunct_thread; |
| + char defunct_tid_path[PATH_MAX]; |
| |
| sigemptyset(&sigusr1); |
| sigaddset(&sigusr1, SIGUSR1); |
| @@ -55,8 +57,9 @@ static void setup(void) |
| TST_CHECKPOINT_WAIT(0); |
| |
| SAFE_PTHREAD_CREATE(&defunct_thread, NULL, defunct_thread_func, NULL); |
| - |
| SAFE_PTHREAD_JOIN(defunct_thread, NULL); |
| + sprintf(defunct_tid_path, "/proc/%d/task/%d", getpid(), defunct_tid); |
| + TST_RETRY_FN_EXP_BACKOFF(access(defunct_tid_path, R_OK), -1, 15); |
| } |
| |
| static void cleanup(void) |
| @@ -108,4 +111,5 @@ static struct tst_test test = { |
| .setup = setup, |
| .cleanup = cleanup, |
| .test = run, |
| + .timeout = 20, |
| }; |
| -- |
| 2.7.4 |
| |