The patch below does not apply to the 4.20-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 227ad6d957898a88b1746e30234ece64d305f066 Mon Sep 17 00:00:00 2001

From: Chris Wilson chris@chris-wilson.co.uk Date: Sun, 30 Dec 2018 12:28:42 +0000 Subject: [PATCH] drm: Reorder set_property_atomic to avoid returning with an active ww_ctx

Delay the drm_modeset_acquire_init() until after we check for an allocation failure so that we can return immediately upon error without having to unwind.

WARNING: lock held when returning to user space! 4.20.0+ #174 Not tainted ------------------------------------------------ syz-executor556/8153 is leaving the kernel with locks still held! 1 lock held by syz-executor556/8153: #0: 000000005100c85c (crtc_ww_class_acquire){+.+.}, at: set_property_atomic+0xb3/0x330 drivers/gpu/drm/drm_mode_object.c:462

Reported-by: syzbot+6ea337c427f5083ebdf2@syzkaller.appspotmail.com Fixes: 144a7999d633 ("drm: Handle properties in the core for atomic drivers") Signed-off-by: Chris Wilson chris@chris-wilson.co.uk Cc: Daniel Vetter daniel.vetter@ffwll.ch Cc: Maarten Lankhorst maarten.lankhorst@linux.intel.com Cc: Sean Paul sean@poorly.run Cc: David Airlie airlied@linux.ie Cc: stable@vger.kernel.org # v4.14+ Reviewed-by: Maarten Lankhorst maarten.lankhorst@linux.intel.com Link: https://patchwork.freedesktop.org/patch/msgid/20181230122842.21917-1-chris@c...

diff --git a/drivers/gpu/drm/drm_mode_object.c b/drivers/gpu/drm/drm_mode_object.c index bb1dd46496cd..a9005c1c2384 100644 --- a/drivers/gpu/drm/drm_mode_object.c +++ b/drivers/gpu/drm/drm_mode_object.c @@ -459,12 +459,13 @@ static int set_property_atomic(struct drm_mode_object *obj, struct drm_modeset_acquire_ctx ctx; int ret;

- drm_modeset_acquire_init(&ctx, 0); - state = drm_atomic_state_alloc(dev); if (!state) return -ENOMEM; + + drm_modeset_acquire_init(&ctx, 0); state->acquire_ctx = &ctx; + retry: if (prop == state->dev->mode_config.dpms_property) { if (obj->type != DRM_MODE_OBJECT_CONNECTOR) {