* thread.c (rb_threadptr_execute_interrupts_common):

  handle timer_interrupt only on the first loop for the case to avoid
  the infinite loop like following case:
  * there is 2 Ruby threads (3 pthreads)
  (1) main thread is waiting at gvl_yield:112 (native_cond_wait)
  (2) sub thread works
  (3) sub thread waits at gvl_yield:133 (native_mutex_unlock)
  (4) main thread works
  (5) main thread goes to gvl_acquire_common
  (6) main thread call rb_wakeup_timer_thread
  (7) timer thread set timer interrupt to the main thread
  (8) main thread works
  (9) main thread waits at gvl_acquire_common:64 (native_cond_wait)
  (10) sub tread works
  (11) set sub thread as the current thread
  (12) run Ruby thread
  (13) ...100ms
  (14) sub thread goes to rb_threadptr_execute_interrupts_common
  (15) sub thread call rb_thread_schedule_limits
  (16) sub thread call gvl_release_common
  (17) sub threads waits at gvl_yield:121 (native_cond_wait)
  (18) main threads works
  (19) main thread back to gvl_yield
  (20) set main thread as the current thread
  (21) main thread call gvl_yield
  (22) main thread waits at gvl_yield:112 (native_cond_wait)
  As described above, the main thread can't escape from
  rb_threadptr_execute_interrupts_common.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@35480 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

2 files changed, 37 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index 2dd3a27542..47cbe0ef5a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,34 @@
+Fri Apr 27 01:45:05 2012  NARUSE, Yui  <naruse@ruby-lang.org>
+
+	* thread.c (rb_threadptr_execute_interrupts_common):
+	  handle timer_interrupt only on the first loop for the case to avoid
+	  the infinite loop like following case:
+	  * there is 2 Ruby threads (3 pthreads)
+	  (1) main thread is waiting at gvl_yield:112 (native_cond_wait)
+	  (2) sub thread works
+	  (3) sub thread waits at gvl_yield:133 (native_mutex_unlock)
+	  (4) main thread works
+	  (5) main thread goes to gvl_acquire_common
+	  (6) main thread call rb_wakeup_timer_thread
+	  (7) timer thread set timer interrupt to the main thread
+	  (8) main thread works
+	  (9) main thread waits at gvl_acquire_common:64 (native_cond_wait)
+	  (10) sub tread works
+	  (11) set sub thread as the current thread
+	  (12) run Ruby thread
+	  (13) ...100ms
+	  (14) sub thread goes to rb_threadptr_execute_interrupts_common
+	  (15) sub thread call rb_thread_schedule_limits
+	  (16) sub thread call gvl_release_common
+	  (17) sub threads waits at gvl_yield:121 (native_cond_wait)
+	  (18) main threads works
+	  (19) main thread back to gvl_yield
+	  (20) set main thread as the current thread
+	  (21) main thread call gvl_yield
+	  (22) main thread waits at gvl_yield:112 (native_cond_wait)
+	  As described above, the main thread can't escape from
+	  rb_threadptr_execute_interrupts_common.
+
 Fri Apr 27 07:15:07 2012  Tanaka Akira  <akr@fsij.org>
 
 	* ext/socket/socket.c (sock_s_pack_sockaddr_un): support the longest
diff --git a/thread.c b/thread.c
index 7383a886f6..a63c9528de 100644
--- a/thread.c
+++ b/thread.c
@@ -1273,6 +1273,7 @@ static void
 rb_threadptr_execute_interrupts_common(rb_thread_t *th)
 {
     rb_atomic_t interrupt;
+    int first_p = TRUE;
 
     if (th->raised_flag) return;
 
@@ -1282,6 +1283,11 @@ rb_threadptr_execute_interrupts_common(rb_thread_t *th)
 	int finalizer_interrupt = interrupt & 0x04;
 	int sig;
 
+	if (first_p)
+	    first_p = FALSE;
+	else if (interrupt == 0x01)
+	    break;
+
 	th->status = THREAD_RUNNABLE;
 
 	/* signal handling */