• Sean Paul's avatar
    drm: damage_helper: Fix race checking plane->state->fb · 354c2d31
    Sean Paul authored
    Since the dirtyfb ioctl doesn't give us any hints as to which plane is
    scanning out the fb it's marking as damaged, we need to loop through
    planes to find it.
    
    Currently we just reach into plane state and check, but that can race
    with another commit changing the fb out from under us. This patch locks
    the plane before checking the fb and will release the lock if the plane
    is not displaying the dirty fb.
    
    Fixes: b9fc5e01 ("drm: Add helper to implement legacy dirtyfb")
    Cc: Rob Clark <robdclark@gmail.com>
    Cc: Deepak Rawat <drawat@vmware.com>
    Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
    Cc: Thomas Hellstrom <thellstrom@vmware.com>
    Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
    Cc: Maxime Ripard <maxime.ripard@bootlin.com>
    Cc: Sean Paul <sean@poorly.run>
    Cc: David Airlie <airlied@linux.ie>
    Cc: Daniel Vetter <daniel@ffwll.ch>
    Cc: dri-devel@lists.freedesktop.org
    Cc: <stable@vger.kernel.org> # v5.0+
    Reported-by: default avatarDaniel Vetter <daniel@ffwll.ch>
    Reviewed-by: default avatarDaniel Vetter <daniel@ffwll.ch>
    Signed-off-by: default avatarSean Paul <seanpaul@chromium.org>
    Link: https://patchwork.freedesktop.org/patch/msgid/20190904202938.110207-1-sean@poorly.run
    354c2d31
drm_damage_helper.c 12.6 KB