From 4d4be202165e832d74849b4a68e289a2a377039c Mon Sep 17 00:00:00 2001 From: Thadeu Lima de Souza Cascardo Date: Mon, 27 Jul 2026 17:45:49 -0300 Subject: [PATCH] drm: Fix drm_crtc_commit leak if signaled when PAGE_FLIP_EVENT is used Commit 1c6ceeee6ebb ("drm/atomic: Fix memleak on ERESTARTSYS during non-blocking commits") fixed a very similar issue when the event was allocated by drm_atomic_helper_setup_commit() itself. However, if the event is allocated in prepare_signaling(), it will also be set to NULL in complete_signaling(), which prevents drm_crtc_commit from being put in __drm_atomic_helper_crtc_destroy_state(). Dropping the reference when the event is set to NULL at complete_signaling() fixes the leak. The leak can be reproduced by sending a signal to the thread using DRM_MODE_PAGE_FLIP_EVENT and using a sw_sync fence to cause the atomic ioctl to block at drm_atomic_helper_wait_for_fences(). It happened both with amdgpu and vkms. Fixes: 24835e442f28 ("drm: reference count event->completion") Cc: stable@vger.kernel.org Signed-off-by: Thadeu Lima de Souza Cascardo Reviewed-by: Melissa Wen Signed-off-by: Melissa Wen Link: https://patch.msgid.link/20260727-drm_crtc_atomic_commit_leak-v1-1-23d9948a9d7c@igalia.com --- drivers/gpu/drm/drm_atomic_uapi.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/gpu/drm/drm_atomic_uapi.c b/drivers/gpu/drm/drm_atomic_uapi.c index 657c15474ed5..ae7667d1072d 100644 --- a/drivers/gpu/drm/drm_atomic_uapi.c +++ b/drivers/gpu/drm/drm_atomic_uapi.c @@ -1560,6 +1560,8 @@ static void complete_signaling(struct drm_device *dev, * to prevent a double free in drm_atomic_commit_clear. */ if (event && (event->base.fence || event->base.file_priv)) { + if (crtc_state->commit && crtc_state->commit->abort_completion) + drm_crtc_commit_put(crtc_state->commit); drm_event_cancel_free(dev, &event->base); crtc_state->event = NULL; }