| Message ID | 20211029024528.8086-2-lizhijian@cn.fujitsu.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [1/2] kselftest: signal all child processes | expand |
On Fri, Oct 29, 2021 at 10:45:28AM +0800, Li Zhijian wrote: > 0Day/LKP observed that the kselftest blocks foever since one of the > pidfd_wait doesn't terminate in 1 of 30 runs. After digging into > the source, we found that it blocks at: > ASSERT_EQ(sys_waitid(P_PIDFD, pidfd, &info, WCONTINUED, NULL), 0); > > we can reproduce it by: > $ while true; do make run_tests -C pidfd; done > > a delay to ensure that the parent can see child process WCONTINUED. > > CC: Christian Brauner <christian@brauner.io> > CC: Shuah Khan <shuah@kernel.org> > CC: Philip Li <philip.li@intel.com> > Reported-by: kernel test robot <lkp@intel.com> > Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com> > --- Not a fan of the usleep() solution but if it fixes it it's fine for a test, I think. Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
On 10/29/21 2:32 AM, Christian Brauner wrote: > On Fri, Oct 29, 2021 at 10:45:28AM +0800, Li Zhijian wrote: >> 0Day/LKP observed that the kselftest blocks foever since one of the >> pidfd_wait doesn't terminate in 1 of 30 runs. After digging into >> the source, we found that it blocks at: >> ASSERT_EQ(sys_waitid(P_PIDFD, pidfd, &info, WCONTINUED, NULL), 0); >> >> we can reproduce it by: >> $ while true; do make run_tests -C pidfd; done >> >> a delay to ensure that the parent can see child process WCONTINUED. >> >> CC: Christian Brauner <christian@brauner.io> >> CC: Shuah Khan <shuah@kernel.org> >> CC: Philip Li <philip.li@intel.com> >> Reported-by: kernel test robot <lkp@intel.com> >> Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com> >> --- > > Not a fan of the usleep() solution but if it fixes it it's fine for > a test, I think. > Acked-by: Christian Brauner <christian.brauner@ubuntu.com> > I don't like introducing usleep() which will increase the kselftest run-time. Every little bit adds up if we allow usleep() in tests. thanks, -- Shuah
On 04/12/2021 01:03, Shuah Khan wrote: > On 10/29/21 2:32 AM, Christian Brauner wrote: >> On Fri, Oct 29, 2021 at 10:45:28AM +0800, Li Zhijian wrote: >>> 0Day/LKP observed that the kselftest blocks foever since one of the >>> pidfd_wait doesn't terminate in 1 of 30 runs. After digging into >>> the source, we found that it blocks at: >>> ASSERT_EQ(sys_waitid(P_PIDFD, pidfd, &info, WCONTINUED, NULL), 0); >>> >>> we can reproduce it by: >>> $ while true; do make run_tests -C pidfd; done >>> >>> a delay to ensure that the parent can see child process WCONTINUED. >>> >>> CC: Christian Brauner <christian@brauner.io> >>> CC: Shuah Khan <shuah@kernel.org> >>> CC: Philip Li <philip.li@intel.com> >>> Reported-by: kernel test robot <lkp@intel.com> >>> Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com> >>> --- >> >> Not a fan of the usleep() solution but if it fixes it it's fine for >> a test, I think. >> Acked-by: Christian Brauner <christian.brauner@ubuntu.com> >> > > I don't like introducing usleep() which will increase the kselftest > run-time. Every little bit adds up if we allow usleep() in tests. Thanks for your comments. how about introduce a pipe to communicate between child and parent. From d68c4629dd60a1e22cb83b771d38e899352ff9a9 Mon Sep 17 00:00:00 2001 From: Li Zhijian <lizhijian@cn.fujitsu.com> Date: Tue, 26 Oct 2021 16:39:56 +0800 Subject: [PATCH] ksefltest: pidfd: Fix wait_states: Test terminated by timeout 0Day/LKP observed that the kselftest blocks foever since one of the pidfd_wait doesn't terminate in 1 of 30 runs. After digging into the source, we found that it blocks at: ASSERT_EQ(sys_waitid(P_PIDFD, pidfd, &info, WCONTINUED, NULL), 0); we can reproduce it by: $ while true; do make run_tests -C pidfd; done Introduce a blocking read in child process to make sure the parent can check its WCONTINUED. CC: Philip Li <philip.li@intel.com> Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com> --- tools/testing/selftests/pidfd/pidfd_wait.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/pidfd/pidfd_wait.c b/tools/testing/selftests/pidfd/pidfd_wait.c index be2943f072f6..d5c0ffa26c32 100644 --- a/tools/testing/selftests/pidfd/pidfd_wait.c +++ b/tools/testing/selftests/pidfd/pidfd_wait.c @@ -96,21 +96,26 @@ TEST(wait_states) .flags = CLONE_PIDFD | CLONE_PARENT_SETTID, .exit_signal = SIGCHLD, }; - int ret; + int ret, pfd[2]; pid_t pid; siginfo_t info = { .si_signo = 0, }; - + ASSERT_EQ(pipe(pfd), 0); pid = sys_clone3(&args); ASSERT_GE(pid, 0); if (pid == 0) { + char buf[2]; + close(pfd[1]); kill(getpid(), SIGSTOP); + ASSERT_EQ(read(pfd[0], buf, 1), 1); + close(pfd[0]); kill(getpid(), SIGSTOP); exit(EXIT_SUCCESS); } + close(pfd[0]); ASSERT_EQ(sys_waitid(P_PIDFD, pidfd, &info, WSTOPPED, NULL), 0); ASSERT_EQ(info.si_signo, SIGCHLD); ASSERT_EQ(info.si_code, CLD_STOPPED); @@ -119,6 +124,8 @@ TEST(wait_states) ASSERT_EQ(sys_pidfd_send_signal(pidfd, SIGCONT, NULL, 0), 0); ASSERT_EQ(sys_waitid(P_PIDFD, pidfd, &info, WCONTINUED, NULL), 0); + ASSERT_EQ(write(pfd[1], "C", 1), 1); + close(pfd[1]); ASSERT_EQ(info.si_signo, SIGCHLD); ASSERT_EQ(info.si_code, CLD_CONTINUED); ASSERT_EQ(info.si_pid, parent_tid);
diff --git a/tools/testing/selftests/pidfd/pidfd_wait.c b/tools/testing/selftests/pidfd/pidfd_wait.c index be2943f072f6..5abd26da4caa 100644 --- a/tools/testing/selftests/pidfd/pidfd_wait.c +++ b/tools/testing/selftests/pidfd/pidfd_wait.c @@ -107,7 +107,9 @@ TEST(wait_states) if (pid == 0) { kill(getpid(), SIGSTOP); + usleep(1000); kill(getpid(), SIGSTOP); + usleep(1000); exit(EXIT_SUCCESS); }
0Day/LKP observed that the kselftest blocks foever since one of the pidfd_wait doesn't terminate in 1 of 30 runs. After digging into the source, we found that it blocks at: ASSERT_EQ(sys_waitid(P_PIDFD, pidfd, &info, WCONTINUED, NULL), 0); we can reproduce it by: $ while true; do make run_tests -C pidfd; done a delay to ensure that the parent can see child process WCONTINUED. CC: Christian Brauner <christian@brauner.io> CC: Shuah Khan <shuah@kernel.org> CC: Philip Li <philip.li@intel.com> Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com> --- tools/testing/selftests/pidfd/pidfd_wait.c | 2 ++ 1 file changed, 2 insertions(+)