On Thu 25 Nov 12:01 CST 2021, Dmitry Baryshkov wrote:
> In case of DPU probe failure, prevent the following NULL pointer
> exception:
>
> [ 3.976112] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000030
> [ 3.984983] Mem abort info:
> [ 3.987800] ESR = 0x96000004
> [ 3.990891] EC = 0x25: DABT (current EL), IL = 32 bits
> [ 3.996251] SET = 0, FnV = 0
> [ 3.996254] EA = 0, S1PTW = 0
> [ 3.996257] FSC = 0x04: level 0 translation fault
> [ 3.996260] Data abort info:
> [ 3.996262] ISV = 0, ISS = 0x00000004
> [ 4.005229] CM = 0, WnR = 0
> [ 4.028893] [0000000000000030] user address but active_mm is swapper
> [ 4.035305] Internal error: Oops: 96000004 [#1] SMP
> [ 4.040223] Modules linked in:
> [ 4.043317] CPU: 1 PID: 50 Comm: kworker/u16:2 Not tainted 5.16.0-rc1-00036-g6d4bafcbb015-dirty #166
> [ 4.052518] Hardware name: Thundercomm Dragonboard 845c (DT)
> [ 4.058224] Workqueue: events_unbound deferred_probe_work_func
> [ 4.064105] pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
> [ 4.071124] pc : dpu_core_irq_uninstall+0x28/0x100
> [ 4.075960] lr : dpu_core_irq_uninstall+0x24/0x100
> [ 4.080793] sp : ffff80001057b990
> [ 4.084138] x29: ffff80001057b990 x28: ffff7653c0a41c00 x27: ffff7653c0926480
> [ 4.091330] x26: ffffb90d5d262ad0 x25: ffff7653c4b2e980 x24: ffff7653c0046080
> [ 4.098520] x23: ffff7653c099a810 x22: ffff7653c5a65800 x21: ffff7653c5a65080
> [ 4.105711] x20: ffff7653c5a65800 x19: ffff7653c0046080 x18: 0000000000000034
> [ 4.112902] x17: 0000000000000038 x16: 0000000000000005 x15: 000000000000000c
> [ 4.120095] x14: 000000000000024c x13: ffff7653c2f90358 x12: 0000000000000000
> [ 4.127287] x11: ffff7653c2f903b0 x10: 00000000000009c0 x9 : ffff80001057b180
> [ 4.134477] x8 : ffff80001057b404 x7 : 0000000000000000 x6 : ffff7653c5a5f190
> [ 4.141669] x5 : ffff80001057b890 x4 : 0000000000000000 x3 : ffff7653c5a5f0f4
> [ 4.148859] x2 : ffff7653c2f50000 x1 : 0000000000000000 x0 : 0000000000000000
> [ 4.156052] Call trace:
> [ 4.158525] dpu_core_irq_uninstall+0x28/0x100
> [ 4.163004] dpu_irq_uninstall+0x10/0x20
> [ 4.166963] msm_drm_uninit.isra.0+0xe0/0x1b0
> [ 4.171353] msm_drm_bind+0x278/0x5f0
> [ 4.175043] try_to_bring_up_master+0x164/0x1d0
> [ 4.179610] __component_add+0xa0/0x170
> [ 4.183482] component_add+0x14/0x20
> [ 4.187086] dsi_dev_probe+0x1c/0x30
> [ 4.190691] platform_probe+0x68/0xe0
> [ 4.194382] really_probe.part.0+0x9c/0x30c
> [ 4.198601] __driver_probe_device+0x98/0x144
> [ 4.202990] driver_probe_device+0x44/0x15c
> [ 4.207208] __device_attach_driver+0xb4/0x120
> [ 4.211685] bus_for_each_drv+0x78/0xd0
> [ 4.215549] __device_attach+0xdc/0x184
> [ 4.219412] device_initial_probe+0x14/0x20
> [ 4.223630] bus_probe_device+0x9c/0xa4
> [ 4.227503] deferred_probe_work_func+0x88/0xc0
> [ 4.232075] process_one_work+0x1e8/0x380
> [ 4.236126] worker_thread+0x280/0x520
> [ 4.239902] kthread+0x168/0x174
> [ 4.243166] ret_from_fork+0x10/0x20
> [ 4.246778] Code: f9442400 91004000 940188b9 f9430660 (b9403001)
> [ 4.252925] ---[ end trace b470a50cd7b5e606 ]---
>
> Signed-off-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 d2b6dca487e3..fc1b6c47c93d 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c
> @@ -575,6 +575,9 @@ void dpu_core_irq_uninstall(struct dpu_kms *dpu_kms)
> {
> int i;
>
> + if (!dpu_kms->hw_intr)
> + return;
I would rather see that we fix msm_drm_init() to nicely unroll things in
a more granular fashion instead of handle all types of errors with the
big hammer that msm_drm_uninit() provides.
Regards,
Bjorn
> +
> 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]))
> --
> 2.33.0
>
