ping
On 17/12/2021 17:30, 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
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
V2: rewrite with pipe to avoid usleep
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]);ASSERT_EQ(read(pfd[0], buf, 1), 1);close(pfd[0]);
- 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);