On 27/04/2022 00:50, Stephen Boyd wrote:
Quoting Vinod Polimera (2022-04-25 23:02:11)
Avoid clearing irqs and derefernce hw_intr when hw_intr is null.
Presumably this is only the case when the display driver doesn't fully
probe and something probe defers? Can you clarify how this situation
happens?
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
Fixes: a73033619ea ("drm/msm/dpu: squash dpu_core_irq into dpu_hw_interrupts")
The fixes tag looks odd. In dpu_core_irq_uninstall() at that commit it
is dealing with 'irq_obj' which isn't a pointer. After commit
f25f656608e3 ("drm/msm/dpu: merge struct dpu_irq into struct
dpu_hw_intr") dpu_core_irq_uninstall() starts using 'hw_intr' which is
allocated on the heap. If we backported this patch to a place that had
a73033619ea without f25f656608e3 it wouldn't make any sense.
I'd agree here. The following tag would be correct:
Fixes: f25f656608e3 ("drm/msm/dpu: merge struct dpu_irq into struct
dpu_hw_intr")
Signed-off-by: Vinod Polimera <quic_vpolimer@xxxxxxxxxxx>
---
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++)
--
With best wishes
Dmitry
