4.4-stable review patch. If anyone has any objections, please let me know.
------------------
[ Upstream commit 699f685569434510d944e419f4048c4e3ba8d631 ]
Using fence->status to determine whether or not there are callbacks
remaining on the sync_fence is racy since fence->status may have been
decremented to 0 on another CPU before fence_check_cb_func() has
completed. By unconditionally calling fence_remove_callback() for each
fence in the sync_fence, we guarantee that each callback has either
completed (since fence_remove_callback() grabs the fence lock) or been
removed.
Signed-off-by: Andrew Bresticker <abrestic@xxxxxxxxxxxx>
Signed-off-by: Dmitry Torokhov <dtor@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/staging/android/sync.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/drivers/staging/android/sync.c b/drivers/staging/android/sync.c
index f83e00c78051..50a9945da27e 100644
--- a/drivers/staging/android/sync.c
+++ b/drivers/staging/android/sync.c
@@ -519,12 +519,10 @@ static const struct fence_ops android_fence_ops = {
static void sync_fence_free(struct kref *kref)
{
struct sync_fence *fence = container_of(kref, struct sync_fence, kref);
- int i, status = atomic_read(&fence->status);
+ int i;
for (i = 0; i < fence->num_fences; ++i) {
- if (status)
- fence_remove_callback(fence->cbs[i].sync_pt,
- &fence->cbs[i].cb);
+ fence_remove_callback(fence->cbs[i].sync_pt, &fence->cbs[i].cb);
fence_put(fence->cbs[i].sync_pt);
}
--
2.19.1
