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(+)
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); }