complete_crtc_signaling is freeing fence_state, but when retrying
num_fences and fence_state are not zero'd. This caused duplicate
fd's in the fence_state array, followed by a BUG_ON in fs/file.c
because we reallocate freed memory, and installing over an existing
fd, or potential other fun.
Zero fence_state and num_fences correctly in the retry loop, which
allows kms_atomic_transition to pass.
Fixes: beaf5af48034 ("drm/fence: add out-fences support")
Cc: Gustavo Padovan <gustavo.padovan@xxxxxxxxxxxxxxx>
Cc: Brian Starkey <brian.starkey@xxxxxxx> (v10)
Cc: Sean Paul <seanpaul@xxxxxxxxxxxx>
Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
Cc: David Airlie <airlied@xxxxxxxx>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # v4.10+
Testcase: kms_atomic_transitions.plane-all-modeset-transition-fencing
(with CONFIG_DEBUG_WW_MUTEX_SLOWPATH=y)
---
drivers/gpu/drm/drm_atomic.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index 1b755439f591..8ec9be4f5d50 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -2203,10 +2203,10 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
struct drm_atomic_state *state;
struct drm_modeset_acquire_ctx ctx;
struct drm_plane *plane;
- struct drm_out_fence_state *fence_state = NULL;
+ struct drm_out_fence_state *fence_state;
unsigned plane_mask;
int ret = 0;
- unsigned int i, j, num_fences = 0;
+ unsigned int i, j, num_fences;
/* disallow for drivers not supporting atomic: */
if (!drm_core_check_feature(dev, DRIVER_ATOMIC))
@@ -2247,6 +2247,8 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
plane_mask = 0;
copied_objs = 0;
copied_props = 0;
+ fence_state = NULL;
+ num_fences = 0;
for (i = 0; i < arg->count_objs; i++) {
uint32_t obj_id, count_props;
--
2.11.0
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