Re: Warnings in DRM code when removing/unbinding a driver

From: Ezequiel Garcia
Date: Tue Dec 17 2019 - 11:35:06 EST


Hi John,

On Mon, 2019-12-16 at 17:23 +0000, John Garry wrote:
> 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

A total shot in the dark. This might make no sense,
but it's worth a try:

diff --git a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
index 2fd4ca91a62d..69bb0e29da88 100644
--- a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
+++ b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
@@ -247,9 +247,8 @@ static int hibmc_unload(struct drm_device *dev)
{
struct hibmc_drm_private *priv = dev->dev_private;

- hibmc_fbdev_fini(priv);
-
drm_atomic_helper_shutdown(dev);
+ hibmc_fbdev_fini(priv);

if (dev->irq_enabled)
drm_irq_uninstall(dev);

Hope it helps,
Ezequiel

> [ 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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