Re: [PATCH 5/8] OPP: Allow multiple clocks for a device

From: Viresh Kumar
Date: Wed Jun 22 2022 - 10:16:17 EST

On 22-06-22, 14:47, Jon Hunter wrote:
> I am seeing the following panic on -next and bisect is point to
> this commit ...
>
> [ 2.145604] 8<--- cut here ---
> [ 2.145615] Unable to handle kernel NULL pointer dereference at virtual address 00000000
> [ 2.145625] [00000000] *pgd=00000000
> [ 2.145647] Internal error: Oops: 80000005 [#1] PREEMPT SMP ARM
> [ 2.145660] Modules linked in:
> [ 2.145671] CPU: 1 PID: 35 Comm: kworker/u8:1 Not tainted 5.19.0-rc3-next-20220622-gf739bc2a47f6 #1
> [ 2.145688] Hardware name: NVIDIA Tegra SoC (Flattened Device Tree)
> [ 2.145697] Workqueue: events_unbound deferred_probe_work_func
> [ 2.145740] PC is at 0x0
> [ 2.145750] LR is at _set_opp+0x194/0x380
> [ 2.145779] pc : [<00000000>] lr : [<c086b578>] psr: 20000013
> [ 2.145789] sp : f08f1c80 ip : c152cb40 fp : c264c040
> [ 2.145798] r10: 00000000 r9 : c152cb40 r8 : c16f3010
> [ 2.145806] r7 : c264c034 r6 : 00000000 r5 : c265d800 r4 : c264c000
> [ 2.145815] r3 : 00000000 r2 : c265d800 r1 : c264c000 r0 : c16f3010
> [ 2.145825] Flags: nzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none
> [ 2.145840] Control: 10c5387d Table: 8000404a DAC: 00000051
> [ 2.145847] Register r0 information: slab kmalloc-1k start c16f3000 pointer offset 16 size 1024
> [ 2.145883] Register r1 information: slab kmalloc-256 start c264c000 pointer offset 0 size 256
> [ 2.145914] Register r2 information: slab kmalloc-128 start c265d800 pointer offset 0 size 128
> [ 2.145942] Register r3 information: NULL pointer
> [ 2.145955] Register r4 information: slab kmalloc-256 start c264c000 pointer offset 0 size 256
> [ 2.145983] Register r5 information: slab kmalloc-128 start c265d800 pointer offset 0 size 128
> [ 2.146012] Register r6 information: NULL pointer
> [ 2.146023] Register r7 information: slab kmalloc-256 start c264c000 pointer offset 52 size 256
> [ 2.146052] Register r8 information: slab kmalloc-1k start c16f3000 pointer offset 16 size 1024
> [ 2.146081] Register r9 information: slab task_struct start c152cb40 pointer offset 0
> [ 2.146105] Register r10 information: NULL pointer
> [ 2.146116] Register r11 information: slab kmalloc-256 start c264c000 pointer offset 64 size 256
> [ 2.146146] Register r12 information: slab task_struct start c152cb40 pointer offset 0
> [ 2.348527] Process kworker/u8:1 (pid: 35, stack limit = 0x(ptrval))
> [ 2.354896] Stack: (0xf08f1c80 to 0xf08f2000)
> [ 2.359273] 1c80: 00000001 c0868db0 00000000 7a13d783 c152cb40 c264c000 c16f3010 c265d800
> [ 2.367471] 1ca0: c2661c40 00000001 c2661c40 00000001 c2661c40 c086b8e8 00000000 7a13d783
> [ 2.375666] 1cc0: c12ea5a0 c265d800 000f4240 c058cfcc ef7dddec 000f4240 00000000 c2661e88
> [ 2.383861] 1ce0: 000f4240 000f4240 c2661e98 c068d238 00000000 c2665e00 000f4240 000f4240
> [ 2.392056] 1d00: c2666258 00000000 c2666000 00000001 c2661c40 c068d15c 00000000 c2666000
> [ 2.400253] 1d20: c16fd140 00000000 c16fd140 00000000 00000000 c16b78b8 c16b5e00 c068d2d8
> [ 2.408450] 1d40: c16b7810 c26661d8 c2666000 c068ed98 c2663d00 c2663d00 00000000 c086914c
> [ 2.416647] 1d60: c2663d00 c16b7810 c068ebec c16b7894 00000004 c0174868 00000000 c16b78b8
> [ 2.424843] 1d80: c16b5e00 c0684630 c16b7810 c068ebec 00000000 00000004 c0174868 c152cb40
> [ 2.433041] 1da0: c16b78b8 c0684794 c16b7810 c068ebec 00000000 c068506c 00000a00 c265e040
> [ 2.441237] 1dc0: c0f5bdd4 00000004 00000000 7a13d783 00000000 c16b7810 c16b7894 00000004
> [ 2.449434] 1de0: 60000013 00000000 c265e10c c265e154 00000000 c06854c4 c265e040 c16b7800
> [ 2.457629] 1e00: c16b7810 c152cb40 00000000 c05e42b0 00000001 00000000 ffffffff 00000000
> [ 2.465824] 1e20: c16b7810 ff8067a4 01000000 7a13d783 c16b7810 c16b7810 00000000 c12f7700
> [ 2.474020] 1e40: 00000000 00000001 c1367c20 c140f00d c1405800 c067a668 c16b7810 00000000
> [ 2.482214] 1e60: c12f7700 c0678280 c16b7810 c12f7700 c16b7810 00000017 00000001 c06784e4
> [ 2.490411] 1e80: c13b6754 f08f1ee4 c16b7810 c0678574 c12f7700 f08f1ee4 c16b7810 c152cb40
> [ 2.498609] 1ea0: 00000001 c06788bc 00000000 f08f1ee4 c0678834 c067675c c1367c20 c14b4e70
> [ 2.506804] 1ec0: c1ea60b8 7a13d783 c16b7810 c16b7810 c152cb40 c16b7854 c12fa050 c067810c
> [ 2.515001] 1ee0: c1400000 c16b7810 00000001 7a13d783 c16b7810 c16b7810 c12fa2f0 c12fa050
> [ 2.523197] 1f00: 00000000 c0677410 c16b7810 c12fa038 c12fa038 c06778d0 c12fa06c c176a180
> [ 2.531394] 1f20: c1405800 c140f000 00000000 c013dd2c c152cb40 c1405800 c1203d40 c176a180
> [ 2.539592] 1f40: c1405800 c140581c c1203d40 c176a198 00000088 c1367177 c1405800 c013e2a4
> [ 2.547790] 1f60: c0f07434 00000000 f08f1f7c c176f7c0 c152cb40 c013e064 c176a180 c176f640
> [ 2.555984] 1f80: f0831eb4 00000000 00000000 c01459b4 c176f7c0 c01458ac 00000000 00000000
> [ 2.564180] 1fa0: 00000000 00000000 00000000 c01001a8 00000000 00000000 00000000 00000000
> [ 2.572373] 1fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
> [ 2.580569] 1fe0: 00000000 00000000 00000000 00000000 00000013 00000000 00000000 00000000
> [ 2.588768] _set_opp from dev_pm_opp_set_opp+0x38/0x78
> [ 2.594038] dev_pm_opp_set_opp from tegra_pmc_core_pd_set_performance_state+0x44/0xb0
> [ 2.602010] tegra_pmc_core_pd_set_performance_state from _genpd_set_performance_state+0x180/0x1d0
> [ 2.611018] _genpd_set_performance_state from _genpd_set_performance_state+0xa4/0x1d0
> [ 2.618972] _genpd_set_performance_state from genpd_set_performance_state+0x50/0x7c
> [ 2.626752] genpd_set_performance_state from genpd_runtime_resume+0x1ac/0x25c
> [ 2.634016] genpd_runtime_resume from __rpm_callback+0x38/0x14c
> [ 2.640073] __rpm_callback from rpm_callback+0x50/0x54
> [ 2.645335] rpm_callback from rpm_resume+0x394/0x7a0
> [ 2.650424] rpm_resume from __pm_runtime_resume+0x4c/0x64
> [ 2.655947] __pm_runtime_resume from host1x_probe+0x29c/0x654
> [ 2.661824] host1x_probe from platform_probe+0x5c/0xb8
> [ 2.667080] platform_probe from really_probe+0xc8/0x2a8
> [ 2.672433] really_probe from __driver_probe_device+0x84/0xe4
> [ 2.678308] __driver_probe_device from driver_probe_device+0x30/0xd0
> [ 2.684789] driver_probe_device from __device_attach_driver+0x88/0xb4
> [ 2.691350] __device_attach_driver from bus_for_each_drv+0x54/0xb4
> [ 2.697647] bus_for_each_drv from __device_attach+0xf0/0x194
> [ 2.703430] __device_attach from bus_probe_device+0x84/0x8c
> [ 2.709129] bus_probe_device from deferred_probe_work_func+0x7c/0xa8
> [ 2.715608] deferred_probe_work_func from process_one_work+0x214/0x54c
> [ 2.722269] process_one_work from worker_thread+0x240/0x508
> [ 2.727960] worker_thread from kthread+0x108/0x124
> [ 2.732872] kthread from ret_from_fork+0x14/0x2c
> [ 2.737602] Exception stack(0xf08f1fb0 to 0xf08f1ff8)
> [ 2.742669] 1fa0: 00000000 00000000 00000000 00000000
> [ 2.750865] 1fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
> [ 2.759061] 1fe0: 00000000 00000000 00000000 00000000 00000013 00000000
> [ 2.765690] Code: bad PC value
> [ 2.768990] ---[ end trace 0000000000000000 ]---
>
>
> Let me know if you have any thoughts.

Maybe I understand what's going on here now, Dmitry too reported this yesterday,
cc'd. Does below fix it for you ?

diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index 2c1ae1286376..a7c7f6f40a7e 100644
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -1120,9 +1120,11 @@ static int _set_opp(struct device *dev, struct opp_table *opp_table,
}
}

- ret = opp_table->config_clks(dev, opp_table, opp, clk_data, scaling_down);
- if (ret)
- return ret;
+ if (opp_table->config_clks) {
+ ret = opp_table->config_clks(dev, opp_table, opp, clk_data, scaling_down);
+ if (ret)
+ return ret;
+ }

/* Scaling down? Configure required OPPs after frequency */
if (scaling_down) {

--
viresh