Merge branch 'linus' into x86/gart

1 files changed, 22 insertions, 18 deletions

diff --git a/kernel/posix-timers.c b/kernel/posix-timers.c
index dbd8398ddb0b..e36d5798cbff 100644
--- a/kernel/posix-timers.c
+++ b/kernel/posix-timers.c
@@ -289,21 +289,29 @@ void do_schedule_next_timer(struct siginfo *info)
                 else
                         schedule_next_timer(timr);
 
-                info->si_overrun = timr->it_overrun_last;
+                info->si_overrun += timr->it_overrun_last;
         }
 
         if (timr)
                 unlock_timer(timr, flags);
 }
 
-int posix_timer_event(struct k_itimer *timr,int si_private)
+int posix_timer_event(struct k_itimer *timr, int si_private)
 {
-        memset(&timr->sigq->info, 0, sizeof(siginfo_t));
+        /*
+         * FIXME: if ->sigq is queued we can race with
+         * dequeue_signal()->do_schedule_next_timer().
+         *
+         * If dequeue_signal() sees the "right" value of
+         * si_sys_private it calls do_schedule_next_timer().
+         * We re-queue ->sigq and drop ->it_lock().
+         * do_schedule_next_timer() locks the timer
+         * and re-schedules it while ->sigq is pending.
+         * Not really bad, but not that we want.
+         */
         timr->sigq->info.si_sys_private = si_private;
-        /* Send signal to the process that owns this timer.*/
 
         timr->sigq->info.si_signo = timr->it_sigev_signo;
-        timr->sigq->info.si_errno = 0;
         timr->sigq->info.si_code = SI_TIMER;
         timr->sigq->info.si_tid = timr->it_id;
         timr->sigq->info.si_value = timr->it_sigev_value;
@@ -435,6 +443,7 @@ static struct k_itimer * alloc_posix_timer(void)
                 kmem_cache_free(posix_timers_cache, tmr);
                 tmr = NULL;
         }
+        memset(&tmr->sigq->info, 0, sizeof(siginfo_t));
         return tmr;
 }
 
@@ -449,9 +458,6 @@ static void release_posix_timer(struct k_itimer *tmr, int it_id_set)
                 spin_unlock_irqrestore(&idr_lock, flags);
         }
         sigqueue_free(tmr->sigq);
-        if (unlikely(tmr->it_process) &&
-            tmr->it_sigev_notify == (SIGEV_SIGNAL|SIGEV_THREAD_ID))
-                put_task_struct(tmr->it_process);
         kmem_cache_free(posix_timers_cache, tmr);
 }
 
@@ -856,11 +862,10 @@ retry_delete:
          * This keeps any tasks waiting on the spin lock from thinking
          * they got something (see the lock code above).
          */
-        if (timer->it_process) {
-                if (timer->it_sigev_notify == (SIGEV_SIGNAL|SIGEV_THREAD_ID))
-                        put_task_struct(timer->it_process);
-                timer->it_process = NULL;
-        }
+        if (timer->it_sigev_notify == (SIGEV_SIGNAL|SIGEV_THREAD_ID))
+                put_task_struct(timer->it_process);
+        timer->it_process = NULL;
+
         unlock_timer(timer, flags);
         release_posix_timer(timer, IT_ID_SET);
         return 0;
@@ -885,11 +890,10 @@ retry_delete:
          * This keeps any tasks waiting on the spin lock from thinking
          * they got something (see the lock code above).
          */
-        if (timer->it_process) {
-                if (timer->it_sigev_notify == (SIGEV_SIGNAL|SIGEV_THREAD_ID))
-                        put_task_struct(timer->it_process);
-                timer->it_process = NULL;
-        }
+        if (timer->it_sigev_notify == (SIGEV_SIGNAL|SIGEV_THREAD_ID))
+                put_task_struct(timer->it_process);
+        timer->it_process = NULL;
+
         unlock_timer(timer, flags);
         release_posix_timer(timer, IT_ID_SET);
 }