Warnings in DRM code when removing/unbinding a driver

John Garry john.garry at huawei.com
Mon Dec 16 17:23:09 UTC 2019


Hi all,

Enabling CONFIG_DEBUG_TEST_DRIVER_REMOVE causes many warns on a system 
with the HIBMC hw:

[   27.788806] WARNING: CPU: 24 PID: 1 at 
drivers/gpu/drm/drm_gem_vram_helper.c:564 bo_driver_move_notify+0x8c/0x98
[   27.798969] Modules linked in:
[   27.802018] CPU: 24 PID: 1 Comm: swapper/0 Tainted: G    B 
  5.5.0-rc1-dirty #565
[   27.810358] Hardware name: Huawei D06 /D06, BIOS Hisilicon D06 UEFI 
RC0 - V1.16.01 03/15/2019
[   27.818872] pstate: 20c00009 (nzCv daif +PAN +UAO)
[   27.823654] pc : bo_driver_move_notify+0x8c/0x98
[   27.828262] lr : bo_driver_move_notify+0x40/0x98
[   27.832868] sp : ffff00236f0677e0
[   27.836173] x29: ffff00236f0677e0 x28: ffffa0001454e5e0
[   27.841476] x27: ffff002366e52128 x26: ffffa000149e67b0
[   27.846779] x25: ffff002366e523e0 x24: ffff002336936120
[   27.852082] x23: ffff0023346f4010 x22: ffff002336936128
[   27.857385] x21: ffffa000149c15c0 x20: ffff0023369361f8
[   27.862687] x19: ffff002336936000 x18: 0000000000001258
[   27.867989] x17: 0000000000001190 x16: 00000000000011d0
[   27.873292] x15: 0000000000001348 x14: ffffa00012d68190
[   27.878595] x13: 0000000000000006 x12: 1ffff40003241f91
[   27.883897] x11: ffff940003241f91 x10: dfffa00000000000
[   27.889200] x9 : ffff940003241f92 x8 : 0000000000000001
[   27.894502] x7 : ffffa0001920fc88 x6 : ffff940003241f92
[   27.899804] x5 : ffff940003241f92 x4 : ffff0023369363a0
[   27.905107] x3 : ffffa00010c104b8 x2 : dfffa00000000000
[   27.910409] x1 : 0000000000000003 x0 : 0000000000000001
[   27.915712] Call trace:
[   27.918151]  bo_driver_move_notify+0x8c/0x98
[   27.922412]  ttm_bo_cleanup_memtype_use+0x54/0x100
[   27.927194]  ttm_bo_put+0x3a0/0x5d0
[   27.930673]  drm_gem_vram_object_free+0xc/0x18
[   27.935109]  drm_gem_object_free+0x34/0xd0
[   27.939196]  drm_gem_object_put_unlocked+0xc8/0xf0
[   27.943978]  hibmc_user_framebuffer_destroy+0x20/0x40
[   27.949020]  drm_framebuffer_free+0x48/0x58
[   27.953194]  drm_mode_object_put.part.1+0x90/0xe8
[   27.957889]  drm_mode_object_put+0x28/0x38
[   27.961976]  hibmc_fbdev_fini+0x54/0x78
[   27.965802]  hibmc_unload+0x2c/0xd0
[   27.969281]  hibmc_pci_remove+0x2c/0x40
[   27.973109]  pci_device_remove+0x6c/0x140
[   27.977110]  really_probe+0x174/0x548
[   27.980763]  driver_probe_device+0x7c/0x148
[   27.984936]  device_driver_attach+0x94/0xa0
[   27.989109]  __driver_attach+0xa8/0x110
[   27.992935]  bus_for_each_dev+0xe8/0x158
[   27.996849]  driver_attach+0x30/0x40
[   28.000415]  bus_add_driver+0x234/0x2f0
[   28.004241]  driver_register+0xbc/0x1d0
[   28.008067]  __pci_register_driver+0xbc/0xd0
[   28.012329]  hibmc_pci_driver_init+0x20/0x28
[   28.016590]  do_one_initcall+0xb4/0x254
[   28.020417]  kernel_init_freeable+0x27c/0x328
[   28.024765]  kernel_init+0x10/0x118
[   28.028245]  ret_from_fork+0x10/0x18
[   28.031813] ---[ end trace 35a83b71b657878d ]---
[   28.036503] ------------[ cut here ]------------
[   28.041115] WARNING: CPU: 24 PID: 1 at 
drivers/gpu/drm/drm_gem_vram_helper.c:40 ttm_buffer_object_destroy+0x4c/0x80
[   28.051537] Modules linked in:
[   28.054585] CPU: 24 PID: 1 Comm: swapper/0 Tainted: G    B   W 
  5.5.0-rc1-dirty #565
[   28.062924] Hardware name: Huawei D06 /D06, BIOS Hisilicon D06 UEFI 
RC0 - V1.16.01 03/15/2019

[snip]

Indeed, simply unbinding the device from the driver causes the same sort 
of issue:

root@(none)$ cd ./bus/pci/drivers/hibmc-drm/
root@(none)$ ls
0000:05:00.0  bind          new_id        remove_id     uevent        unbind
root@(none)$ echo 0000\:05\:00.0 > unbind
[  116.074352] ------------[ cut here ]------------
[  116.078978] WARNING: CPU: 17 PID: 1178 at 
drivers/gpu/drm/drm_gem_vram_helper.c:40 ttm_buffer_object_destroy+0x4c/0x80
[  116.089661] Modules linked in:
[  116.092711] CPU: 17 PID: 1178 Comm: sh Tainted: G    B   W 
5.5.0-rc1-dirty #565
[  116.100704] Hardware name: Huawei D06 /D06, BIOS Hisilicon D06 UEFI 
RC0 - V1.16.01 03/15/2019
[  116.109218] pstate: 20400009 (nzCv daif +PAN -UAO)
[  116.114001] pc : ttm_buffer_object_destroy+0x4c/0x80
[  116.118956] lr : ttm_buffer_object_destroy+0x18/0x80
[  116.123910] sp : ffff0022e6cef8e0
[  116.127215] x29: ffff0022e6cef8e0 x28: ffff00231b1fb000
[  116.132519] x27: 0000000000000000 x26: ffff00231b1fb000
[  116.137821] x25: ffff0022e6cefdc0 x24: 0000000000002480
[  116.143124] x23: ffff0023682b6ab0 x22: ffff0023682b6800
[  116.148427] x21: ffff0023682b6800 x20: 0000000000000000
[  116.153730] x19: ffff0023682b6800 x18: 0000000000000000
[  116.159032] x17: 000000000000000000000000001
[  116.185545] x7 : ffff0023682b6b07 x6 : ffff80046d056d61
[  116.190848] x5 : ffff80046d056d61 x4 : ffff0023682b6ba0
[  116.196151] x3 : ffffa00010197338 x2 : dfffa00000000000
[  116.201453] x1 : 0000000000000003 x0 : 0000000000000001
[  116.206756] Call trace:
[  116.209195]  ttm_buffer_object_destroy+0x4c/0x80
[  116.213803]  ttm_bo_release_list+0x184/0x220
[  116.218064]  ttm_bo_put+0x410/0x5d0
[  116.221544]  drm_gem_vram_object_free+0xc/0x18
[  116.225979]  drm_gem_object_free+0x34/0xd0
[  116.230066]  drm_gem_object_put_unlocked+0xc8/0xf0
[  116.234848]  hibmc_user_framebuffer_destroy+0x20/0x40
[  116.239890]  drm_framebuffer_free+0x48/0x58
[  116.244064]  drm_mode_object_put.part.1+0x90/0xe8
[  116.248759]  drm_mode_object_put+0x28/0x38
[  116.252846]  hibmc_fbdev_fini+0x54/0x78
[  116.256672]  hibmc_unload+0x2c/0xd0
[  116.260151]  hibmc_pci_remove+0x2c/0x40
[  116.263979]  pci_device_remove+0x6c/0x140
[  116.267980]  device_release_driver_internal+0x134/0x250
[  116.273196]  device_driver_detach+0x28/0x38
[  116.277369]  unbind_store+0xfc/0x150
[  116.280934]  drv_attr_store+0x48/0x60
[  116.284589]  sysfs_kf_write+0x80/0xb0
[  116.288241]  kernfs_fop_write+0x1d4/0x320
[  116.292243]  __vfs_write+0x54/0x98
[  116.295635]  vfs_write+0xe8/0x270
[  116.298940]  ksys_write+0xc8/0x180
[  116.302333]  __arm64_sys_write+0x40/0x50
[  116.306248]  el0_svc_common.constprop.0+0xa4/0x1f8
[  116.311029]  el0_svc_handler+0x34/0xb0
[  116.314770]  el0_sync_handler+0x10c/0x1c8
[  116.318769]  el0_sync+0x140/0x180
[  116.322074] ---[ end trace e60e43d0e316b5c8 ]---
[  116.326868] ------------[ cut here ]------------


dmesg and .config is here:
https://pastebin.com/4P5yaZBS

I'm not sure if this is a HIBMC driver issue or issue with the framework.

john




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