Hi Qian, First of all thanks for testing this, I need more of your help to test this out :) FWIW, I did test this on my Hikey board today, with some hacks, and tried multiple insmod/rmmod operations for the driver, and I wasn't able to reproduce the issue you reported. I did enable the list-debug config option. On 14-06-21, 09:48, Qian Cai wrote: > Unfortunately, this series looks like needing more works. > > [ 487.773586][ T0] CPU17: Booted secondary processor 0x0000000801 [0x503f0002] > [ 487.976495][ T670] list_del corruption. next->prev should be ffff009b66e9ec70, but was ffff009b66dfec70 > [ 487.987037][ T670] ------------[ cut here ]------------ > [ 487.992351][ T670] kernel BUG at lib/list_debug.c:54! > [ 487.997810][ T670] Internal error: Oops - BUG: 0 [#1] SMP > [ 488.003295][ T670] Modules linked in: cpufreq_userspace xfs loop cppc_cpufreq processor efivarfs ip_tables x_tables ext4 mbcache jbd2 dm_mod igb i2c_algo_bit nvme mlx5_core i2c_core nvme_core firmware_class > [ 488.021759][ T670] CPU: 1 PID: 670 Comm: cppc_fie Not tainted 5.13.0-rc5-next-20210611+ #46 > [ 488.030190][ T670] Hardware name: MiTAC RAPTOR EV-883832-X3-0001/RAPTOR, BIOS 1.6 06/28/2020 > [ 488.038705][ T670] pstate: 600000c5 (nZCv daIF -PAN -UAO -TCO BTYPE=--) > [ 488.045398][ T670] pc : __list_del_entry_valid+0x154/0x158 > [ 488.050969][ T670] lr : __list_del_entry_valid+0x154/0x158 > [ 488.056534][ T670] sp : ffff8000229afd70 > [ 488.060534][ T670] x29: ffff8000229afd70 x28: ffff0008c8f4f340 x27: dfff800000000000 > [ 488.068361][ T670] x26: ffff009b66e9ec70 x25: ffff800011c8b4d0 x24: ffff0008d4bfe488 > [ 488.076188][ T670] x23: ffff0008c8f4f340 x22: ffff0008c8f4f340 x21: ffff009b6789ec70 > [ 488.084015][ T670] x20: ffff0008d4bfe4c8 x19: ffff009b66e9ec70 x18: ffff0008c8f4fd70 > [ 488.091842][ T670] x17: 20747562202c3037 x16: 6365396536366239 x15: 0000000000000028 > [ 488.099669][ T670] x14: 0000000000000000 x13: 0000000000000001 x12: ffff60136cdd3447 > [ 488.107495][ T670] x11: 1fffe0136cdd3446 x10: ffff60136cdd3446 x9 : ffff8000103ee444 > [ 488.115322][ T670] x8 : ffff009b66e9a237 x7 : 0000000000000001 x6 : ffff009b66e9a230 > [ 488.123149][ T670] x5 : 00009fec9322cbba x4 : ffff60136cdd3447 x3 : 1fffe001191e9e69 > [ 488.130975][ T670] x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000054 > [ 488.138803][ T670] Call trace: > [ 488.141935][ T670] __list_del_entry_valid+0x154/0x158 > [ 488.147153][ T670] kthread_worker_fn+0x15c/0xda0 This is a strange place to get the issue from. And this is a new issue. > [ 488.151939][ T670] kthread+0x3ac/0x460 > [ 488.155854][ T670] ret_from_fork+0x10/0x18 > [ 488.160120][ T670] Code: 911e8000 aa1303e1 910a0000 941b595b (d4210000) > [ 488.166901][ T670] ---[ end trace e637e2d38b2cc087 ]--- > [ 488.172206][ T670] Kernel panic - not syncing: Oops - BUG: Fatal exception > [ 488.179182][ T670] SMP: stopping secondary CPUs > [ 489.209347][ T670] SMP: failed to stop secondary CPUs 0-1,10-11,16-17,31 > [ 489.216128][ T][ T670] Memoryn ]--- Can you give details on what exactly did you try to do, to get this ? Normal boot or something more ? I have made some changes to the way calls were happening, may get this thing sorted. Can you please try this branch ? https://git.kernel.org/pub/scm/linux/kernel/git/vireshk/pm.git/log/?h=cpufreq/cppc I can see one place where race can happen, i.e. between topology_clear_scale_freq_source() and topology_scale_freq_tick(). It is possible that sfd->set_freq_scale() may get called for a previously set handler as there is no protection there. I will see how to fix that. But I am not sure if the issue reported above comes from there. Anyway, please give my branch a try, lets see. -- viresh
