[v3] drm/msm/disp/dpu1: avoid clearing hw interrupts if hw_intr is null during drm uninit

[Vinod Polimera]

If dp modeset init is failed due to panel being not ready and
probe defers during drm bind, avoid clearing irqs and dereference
hw_intr when hw_intr is null.

BUG: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000

Call trace:
 dpu_core_irq_uninstall+0x50/0xb0
 dpu_irq_uninstall+0x18/0x24
 msm_drm_uninit+0xd8/0x16c
 msm_drm_bind+0x580/0x5fc
 try_to_bring_up_master+0x168/0x1c0
 __component_add+0xb4/0x178
 component_add+0x1c/0x28
 dp_display_probe+0x38c/0x400
 platform_probe+0xb0/0xd0
 really_probe+0xcc/0x2c8
 __driver_probe_device+0xbc/0xe8
 driver_probe_device+0x48/0xf0
 __device_attach_driver+0xa0/0xc8
 bus_for_each_drv+0x8c/0xd8
 __device_attach+0xc4/0x150
 device_initial_probe+0x1c/0x28

Changes in V2:
- Update commit message and correct fixes tag.

Changes in V3:
- Misc changes in commit text.

Fixes: f25f656608e3 ("drm/msm/dpu: merge struct dpu_irq into struct dpu_hw_intr")
Signed-off-by: Vinod Polimera <quic_vpolimer@xxxxxxxxxxx>
Reviewed-by: Stephen Boyd <swboyd@xxxxxxxxxxxx>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
---
 drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c
index c515b7c..ab28577 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c
@@ -599,6 +599,9 @@ void dpu_core_irq_uninstall(struct dpu_kms *dpu_kms)
 {
 	int i;
 
+	if (!dpu_kms->hw_intr)
+		return;
+
 	pm_runtime_get_sync(&dpu_kms->pdev->dev);
 	for (i = 0; i < dpu_kms->hw_intr->total_irqs; i++)
 		if (!list_empty(&dpu_kms->hw_intr->irq_cb_tbl[i]))
-- 
2.7.4