From 24c979bdeaa8883a6d24139190ba5a4fc970e190 Mon Sep 17 00:00:00 2001 From: normal Date: Tue, 29 Dec 2015 18:20:27 +0000 Subject: thread_pthread.c (rb_thread_create_timer_thread): fix race This fixes an occasional [ASYNC BUG] failure in bootstraptest/test_fork.rb '[ruby-dev:37934]' which tests fork/pthread_create failure by setting RLIMIT_NPROC to 1 and triggering EAGAIN on pthread_create when attempting to recreate the timer thread. The problem timeline is as follows: thread 1 thread 2 --------------------------------------------------------------- rb_thread_create_timer_thread setup_communication_pipe rb_thread_wakeup_timer_thread_low pthread_create fails pipe looks valid, write! CLOSE_INVALIDATE (x4) EBADF -> ASYNC BUG The checks in rb_thread_wakeup_timer_thread_low only tried to guarantee proper ordering with native_stop_timer_thread, not rb_thread_create_timer_thread :x Now, this should allow rb_thread_create_timer_thread to synchronize properly with rb_thread_wakeup_timer_thread_low by delaying the validation marking of the timer_thread_pipe until we are certain the timer thread is alive. In this version, rb_thread_wakeup_timer_thread_low becomes a noop. Threading is still completely broken with NPROC==1, but there's not much we can do about it beside warn the user. We no longer spew a scary [ASYNC BUG] message or dump core on them. * thread_pthread.c (setup_communication_pipe): delay setting owner (rb_thread_create_timer_thread): until thread creation succeeds [ruby-core:72590] [Bug #11922] git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53373 b2dd03c8-39d4-4d8f-98ff-823fe69b080e --- thread_pthread.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'thread_pthread.c') diff --git a/thread_pthread.c b/thread_pthread.c index 2a15816713..46cc5715c4 100644 --- a/thread_pthread.c +++ b/thread_pthread.c @@ -1406,8 +1406,6 @@ setup_communication_pipe(void) return e; } - /* validate pipe on this process */ - timer_thread_pipe.owner_process = getpid(); return 0; } @@ -1615,6 +1613,9 @@ rb_thread_create_timer_thread(void) #endif return; } + + /* validate pipe on this process */ + timer_thread_pipe.owner_process = getpid(); timer_thread.created = 1; #ifdef HAVE_PTHREAD_ATTR_INIT pthread_attr_destroy(&attr); -- cgit v1.2.3