drm/tegra: dc: Fix a potential race on page-flip completion
Page-flip completion could race with page-flip submission, so extend the
critical section to include all accesses to page-flip related data.
Reported-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
diff --git a/drivers/gpu/drm/tegra/dc.c b/drivers/gpu/drm/tegra/dc.c
index 5a6d43d..ef36f9d 100644
--- a/drivers/gpu/drm/tegra/dc.c
+++ b/drivers/gpu/drm/tegra/dc.c
@@ -814,8 +814,12 @@
unsigned long flags, base;
struct tegra_bo *bo;
- if (!dc->event)
+ spin_lock_irqsave(&drm->event_lock, flags);
+
+ if (!dc->event) {
+ spin_unlock_irqrestore(&drm->event_lock, flags);
return;
+ }
bo = tegra_fb_get_plane(crtc->primary->fb, 0);
@@ -825,12 +829,12 @@
tegra_dc_writel(dc, 0, DC_CMD_STATE_ACCESS);
if (base == bo->paddr + crtc->primary->fb->offsets[0]) {
- spin_lock_irqsave(&drm->event_lock, flags);
drm_crtc_send_vblank_event(crtc, dc->event);
drm_crtc_vblank_put(crtc);
dc->event = NULL;
- spin_unlock_irqrestore(&drm->event_lock, flags);
}
+
+ spin_unlock_irqrestore(&drm->event_lock, flags);
}
void tegra_dc_cancel_page_flip(struct drm_crtc *crtc, struct drm_file *file)