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| author | Alan Modra <amodra@gmail.com> | 2013-01-22 22:11:53 +1030 |
|---|---|---|
| committer | Alan Modra <amodra@gcc.gnu.org> | 2013-01-22 22:11:53 +1030 |
| commit | 9a6472882361988c2a97751dde13aa37f46def16 (patch) | |
| tree | fe198ebe6a2ed3b92472162492a8abbaf38411da /libgomp | |
| parent | e18600419eb270e0073c45a8da5aa9c7ab10ee77 (diff) | |
| download | gcc-9a6472882361988c2a97751dde13aa37f46def16.zip gcc-9a6472882361988c2a97751dde13aa37f46def16.tar.gz gcc-9a6472882361988c2a97751dde13aa37f46def16.tar.bz2 | |
re PR libgomp/51376 (libgomp taskwait failure)
PR libgomp/51376
PR libgomp/56073
* task.c (GOMP_task): Revert 2011-12-09 change.
(GOMP_taskwait): Likewise. Instead use atomic load with acquire
barrier to read task->children..
(gomp_barrier_handle_tasks): ..and matching atomic store with
release barrier here when setting parent->children to NULL.
From-SVN: r195370
Diffstat (limited to 'libgomp')
| -rw-r--r-- | libgomp/ChangeLog | 10 | ||||
| -rw-r--r-- | libgomp/task.c | 16 |
2 files changed, 21 insertions, 5 deletions
diff --git a/libgomp/ChangeLog b/libgomp/ChangeLog index 3bc553a..266a66e 100644 --- a/libgomp/ChangeLog +++ b/libgomp/ChangeLog @@ -1,3 +1,13 @@ +2013-01-22 Alan Modra <amodra@gmail.com> + + PR libgomp/51376 + PR libgomp/56073 + * task.c (GOMP_task): Revert 2011-12-09 change. + (GOMP_taskwait): Likewise. Instead use atomic load with acquire + barrier to read task->children.. + (gomp_barrier_handle_tasks): ..and matching atomic store with + release barrier here when setting parent->children to NULL. + 2013-01-16 Jakub Jelinek <jakub@redhat.com> Tobias Burnus <burnus@net-b.de> diff --git a/libgomp/task.c b/libgomp/task.c index be8b431..937f266 100644 --- a/libgomp/task.c +++ b/libgomp/task.c @@ -116,11 +116,10 @@ GOMP_task (void (*fn) (void *), void *data, void (*cpyfn) (void *, void *), } else fn (data); - if (team != NULL) + if (task.children != NULL) { gomp_mutex_lock (&team->task_lock); - if (task.children != NULL) - gomp_clear_parent (task.children); + gomp_clear_parent (task.children); gomp_mutex_unlock (&team->task_lock); } gomp_end_task (); @@ -258,7 +257,13 @@ gomp_barrier_handle_tasks (gomp_barrier_state_t state) parent->children = child_task->next_child; else { - parent->children = NULL; + /* We access task->children in GOMP_taskwait + outside of the task lock mutex region, so + need a release barrier here to ensure memory + written by child_task->fn above is flushed + before the NULL is written. */ + __atomic_store_n (&parent->children, NULL, + MEMMODEL_RELEASE); if (parent->in_taskwait) gomp_sem_post (&parent->taskwait_sem); } @@ -291,7 +296,8 @@ GOMP_taskwait (void) struct gomp_task *child_task = NULL; struct gomp_task *to_free = NULL; - if (task == NULL || team == NULL) + if (task == NULL + || __atomic_load_n (&task->children, MEMMODEL_ACQUIRE) == NULL) return; gomp_mutex_lock (&team->task_lock); |