2017-08-14 Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>:
> 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(-)
Reviewed-by: Gustavo Padovan <gustavo.padovan@xxxxxxxxxxxxx>
Gustavo