Merge tag 'drm-fixes-2023-08-25' of git://anongit.freedesktop.org/drm/drm

Pull drm fixes from Dave Airlie:
 "A bit bigger than I'd care for, but it's mostly a single vmwgfx fix
  and a fix for an i915 hotplug probing. Otherwise misc i915, bridge,
  panfrost and dma-buf fixes.

  core:
   - add a HPD poll helper

  i915:
   - fix regression in i915 polling
   - fix docs build warning
   - fix DG2 idle power consumption

  bridge:
   - samsung-dsim: init fix

  panfrost:
   - fix speed binning issue

  dma-buf:
   - fix recursive lock in fence signal

  vmwgfx:
   - fix shader stage validation
   - fix NULL ptr derefs in gem put"

* tag 'drm-fixes-2023-08-25' of git://anongit.freedesktop.org/drm/drm:
  drm/i915: Fix HPD polling, reenabling the output poll work as needed
  drm: Add an HPD poll helper to reschedule the poll work
  drm/vmwgfx: Fix possible invalid drm gem put calls
  drm/vmwgfx: Fix shader stage validation
  dma-buf/sw_sync: Avoid recursive lock during fence signal
  drm/i915: fix Sphinx indentation warning
  drm/i915/dgfx: Enable d3cold at s2idle
  drm/display/dp: Fix the DP DSC Receiver cap size
  drm/panfrost: Skip speed binning on EOPNOTSUPP
  drm: bridge: samsung-dsim: Fix init during host transfer

1 files changed, 9 insertions, 9 deletions

diff --git a/drivers/dma-buf/sw_sync.c b/drivers/dma-buf/sw_sync.c
index 63f0aeb66db6..f0a35277fd84 100644
--- a/drivers/dma-buf/sw_sync.c
+++ b/drivers/dma-buf/sw_sync.c
@@ -191,6 +191,7 @@ static const struct dma_fence_ops timeline_fence_ops = {
  */
 static void sync_timeline_signal(struct sync_timeline *obj, unsigned int inc)
 {
+	LIST_HEAD(signalled);
 	struct sync_pt *pt, *next;
 
 	trace_sync_timeline(obj);
@@ -203,21 +204,20 @@ static void sync_timeline_signal(struct sync_timeline *obj, unsigned int inc)
 		if (!timeline_fence_signaled(&pt->base))
 			break;
 
-		list_del_init(&pt->link);
+		dma_fence_get(&pt->base);
+
+		list_move_tail(&pt->link, &signalled);
 		rb_erase(&pt->node, &obj->pt_tree);
 
-		/*
-		 * A signal callback may release the last reference to this
-		 * fence, causing it to be freed. That operation has to be
-		 * last to avoid a use after free inside this loop, and must
-		 * be after we remove the fence from the timeline in order to
-		 * prevent deadlocking on timeline->lock inside
-		 * timeline_fence_release().
-		 */
 		dma_fence_signal_locked(&pt->base);
 	}
 
 	spin_unlock_irq(&obj->lock);
+
+	list_for_each_entry_safe(pt, next, &signalled, link) {
+		list_del_init(&pt->link);
+		dma_fence_put(&pt->base);
+	}
 }
 
 /**