STINNER Victor <victor.stin...@haypocalc.com> added the comment: sigprocmask or (better) pthread_sigmask is required to fix #11859 bug.
--- Python has a test for "broken pthread_sigmask". Extract of configure.in: AC_MSG_CHECKING(if PTHREAD_SCOPE_SYSTEM is supported) AC_CACHE_VAL(ac_cv_pthread_system_supported, [AC_RUN_IFELSE([AC_LANG_SOURCE([[#include <pthread.h> void *foo(void *parm) { return NULL; } main() { pthread_attr_t attr; pthread_t id; if (pthread_attr_init(&attr)) exit(-1); if (pthread_attr_setscope(&attr, PTHREAD_SCOPE_SYSTEM)) exit(-1); if (pthread_create(&id, &attr, foo, NULL)) exit(-1); exit(0); }]])], [ac_cv_pthread_system_supported=yes], [ac_cv_pthread_system_supported=no], [ac_cv_pthread_system_supported=no]) ]) AC_MSG_RESULT($ac_cv_pthread_system_supported) if test "$ac_cv_pthread_system_supported" = "yes"; then AC_DEFINE(PTHREAD_SYSTEM_SCHED_SUPPORTED, 1, [Defined if PTHREAD_SCOPE_SYSTEM supported.]) fi AC_CHECK_FUNCS(pthread_sigmask, [case $ac_sys_system in CYGWIN*) AC_DEFINE(HAVE_BROKEN_PTHREAD_SIGMASK, 1, [Define if pthread_sigmask() does not work on your system.]) ;; esac]) Extract of Python/thread_pthread.h: /* On platforms that don't use standard POSIX threads pthread_sigmask() * isn't present. DEC threads uses sigprocmask() instead as do most * other UNIX International compliant systems that don't have the full * pthread implementation. */ #if defined(HAVE_PTHREAD_SIGMASK) && !defined(HAVE_BROKEN_PTHREAD_SIGMASK) # define SET_THREAD_SIGMASK pthread_sigmask #else # define SET_THREAD_SIGMASK sigprocmask #endif --- Because today more and more programs rely on threads, it is maybe not a good idea to provide a binding of sigprocmask(). I would prefer to only add pthread_sigmask() which has a determistic behaviour with threads. So only compile signal.pthread_sigmask() if pthread API is present and pthread_sigmask "is not broken". --- About the patch: the doc should explain that the signal masks are inherited for child processes (fork() and execve()). I don't know if this behaviour is specific to Linux or not. If we only use pthread_sigmask(), the doc is wrong: "Set the signal mask for the process." It's not for the process but only for the current thread. How does it work if I change the signal mask of the main thread and then I create a new thread: the signal mask is inherited, or a default mask is used instead? --- The new faulthandler uses a thread to implement a timeout: the thread uses pthread_sigmask() or sigprocmask() to ignore all signals. If I don't set the signal mask, some tests fail: check that a system call (like reading from a pipe) can be interrupted by signal. The problem is that signal may be send to the faulthandler thread, instead of the main thread. Hum, while I'm writing this, I realize that I should maybe not fallback to sigprocmask() because it may mask signals for the whole process (all threads)! ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue8407> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com