From: Quanyang Wang <quanyang.w...@windriver.com>

commit a7e02f7796c163ac8297b30223bf24bade9f8a50 upstream

When running xrandr to change resolution of DP, the kmemleak as below
can be observed:

unreferenced object 0xffff00080a351000 (size 256):
  comm "Xorg", pid 248, jiffies 4294899614 (age 19.960s)
  hex dump (first 32 bytes):
    98 a0 bc 01 08 00 ff ff 01 00 00 00 00 00 00 00  ................
    ff ff ff ff 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<00000000e0bd0f69>] kmemleak_alloc+0x30/0x40
    [<00000000cde2f318>] kmem_cache_alloc+0x3d4/0x588
    [<0000000088ea9bd7>] drm_atomic_helper_setup_commit+0x84/0x5f8
    [<000000002290a264>] drm_atomic_helper_commit+0x58/0x388
    [<00000000f6ea78c3>] drm_atomic_commit+0x4c/0x60
    [<00000000c8e0725e>] drm_atomic_connector_commit_dpms+0xe8/0x110
    [<0000000020ade187>] drm_mode_obj_set_property_ioctl+0x1b0/0x450
    [<00000000918206d6>] drm_connector_property_set_ioctl+0x3c/0x68
    [<000000008d51e7a5>] drm_ioctl_kernel+0xc4/0x118
    [<000000002a819b75>] drm_ioctl+0x214/0x448
    [<000000008ca4e588>] __arm64_sys_ioctl+0xa8/0xf0
    [<0000000034e15a35>] el0_svc_common.constprop.0+0x74/0x190
    [<000000001b93d916>] do_el0_svc+0x24/0x90
    [<00000000ce9230e0>] el0_svc+0x14/0x20
    [<00000000e3607d82>] el0_sync_handler+0xb0/0xb8
    [<000000003e79c15f>] el0_sync+0x174/0x180

This is because there is a scenario that a drm_crtc_commit commit is
allocated but not freed. The drm subsystem require/release references
to a CRTC commit by calling drm_crtc_commit_get/put, and when
drm_crtc_commit_put find that commit.ref.refcount is zero, it will
call __drm_crtc_commit_free to free this CRTC commit. Among these
drm_crtc_commit_get/put pairs, there is a drm_crtc_commit_get in
drm_atomic_helper_setup_commit as below:

...
new_crtc_state->event->base.completion = &commit->flip_done;
new_crtc_state->event->base.completion_release = release_crtc_commit;
drm_crtc_commit_get(commit);
...

This reference to the CRTC commit should be released at the function
release_crtc_commit by calling e->completion_release(e->completion) in
drm_send_event_locked. So we need to call drm_send_event_locked at
two places: handling vblank event in the irq handler and the crtc disable
helper. But in zynqmp_disp_crtc_atomic_disable, it only marks the flip
is done and not call drm_crtc_commit_put. This result that the refcount
of this commit is always non-zero and this commit will never be freed.

Since the function drm_crtc_send_vblank_event has operations both sending
a flip_done signal and releasing reference to the CRTC commit, let's use
it instead.

Signed-off-by: Quanyang Wang <quanyang.w...@windriver.com>
Signed-off-by: Daniel Vetter <daniel.vet...@ffwll.ch>
Link: 
https://patchwork.freedesktop.org/patch/msgid/20210202064121.173362-1-quanyang.w...@windriver.com
---
Hi Bruce,
Would you please help merge this patch to the branches:
        v6.1/standard/preempt-rt/sdkv6.1/xlnx-soc
        v6.1/standard/sdkv6.1/xlnx-soc
Thanks,
Quanyang
---
 drivers/gpu/drm/xlnx/zynqmp_disp.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/xlnx/zynqmp_disp.c 
b/drivers/gpu/drm/xlnx/zynqmp_disp.c
index c86e7a7775c5f..69fc2c48579fd 100644
--- a/drivers/gpu/drm/xlnx/zynqmp_disp.c
+++ b/drivers/gpu/drm/xlnx/zynqmp_disp.c
@@ -2043,8 +2043,6 @@ static void zynqmp_disp_enable(struct zynqmp_disp *disp)
  */
 static void zynqmp_disp_disable(struct zynqmp_disp *disp, bool force)
 {
-       struct drm_crtc *crtc = &disp->xlnx_crtc.crtc;
-
        if (!force && (!disp->enabled || zynqmp_disp_layer_is_enabled(disp)))
                return;
 
@@ -2053,12 +2051,6 @@ static void zynqmp_disp_disable(struct zynqmp_disp 
*disp, bool force)
        zynqmp_disp_av_buf_disable_buf(&disp->av_buf);
        zynqmp_disp_av_buf_disable(&disp->av_buf);
 
-       /* Mark the flip is done as crtc is disabled anyway */
-       if (crtc->state->event) {
-               complete_all(crtc->state->event->base.completion);
-               crtc->state->event = NULL;
-       }
-
        disp->enabled = false;
 }
 
@@ -2636,8 +2628,16 @@ zynqmp_disp_crtc_atomic_disable(struct drm_crtc *crtc,
        zynqmp_disp_clk_disable(disp->pclk, &disp->pclk_en);
        zynqmp_disp_plane_disable(crtc->primary);
        zynqmp_disp_disable(disp, true);
-       if (!disp->dpsub->external_crtc_attached)
+       if (!disp->dpsub->external_crtc_attached) {
                drm_crtc_vblank_off(crtc);
+
+               spin_lock_irq(&crtc->dev->event_lock);
+               if (crtc->state->event) {
+                       drm_crtc_send_vblank_event(crtc, crtc->state->event);
+                       crtc->state->event = NULL;
+               }
+               spin_unlock_irq(&crtc->dev->event_lock);
+       }
        pm_runtime_put_sync(disp->dev);
 }
 
-- 
2.36.1

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