Recently we committed a fix to allow processes to receive notifications for non-zero exits via the process connector module. Commit is a4c9a56e6a2c. However, for threads, when it does a pthread_exit(&exit_status) call, the kernel is not aware of the exit status with which pthread_exit is called. It is sent by child thread to the parent process, if it is waiting in pthread_join(). Hence, for a thread exiting abnormally, kernel cannot send notifications to any listening processes. The exception to this is if the thread is sent a signal which it has not handled, and dies along with it's process as a result; for eg. SIGSEGV or SIGKILL. In this case, kernel is aware of the non-zero exit and sends a notification for it. For our use case, we cannot have parent wait in pthread_join, one of the main reasons for this being that we do not want to track normal pthread_exit(), which could be a very large number. We only want to be notified of any abnormal exits. Hence, threads are created with pthread_attr_t set to PTHREAD_CREATE_DETACHED. To fix this problem, we add a new type PROC_CN_MCAST_NOTIFY to proc connector API, which allows a thread to send it's exit status to kernel either when it needs to call pthread_exit() with non-zero value to indicate some error or from signal handler before pthread_exit(). Anjali Kulkarni (2): connector/cn_proc: Handle threads for proc connector connector/cn_proc: Selftest for threads case drivers/connector/cn_proc.c | 11 ++- include/linux/cn_proc.h | 5 +- include/uapi/linux/cn_proc.h | 4 +- kernel/exit.c | 5 +- tools/testing/selftests/connector/Makefile | 23 ++++- .../testing/selftests/connector/proc_filter.c | 5 + tools/testing/selftests/connector/thread.c | 87 +++++++++++++++++ .../selftests/connector/thread_filter.c | 93 +++++++++++++++++++ 8 files changed, 226 insertions(+), 7 deletions(-) create mode 100644 tools/testing/selftests/connector/thread.c create mode 100644 tools/testing/selftests/connector/thread_filter.c -- 2.45.2
