Re: [PATCH] drm/amdkfd: fix svm_migrate_fini warning

[Andrey Grodzovsky]

In any case, once you converge on solution please include
the relevant ticket in the commit description  -

https://gitlab.freedesktop.org/drm/amd/-/issues/1718

Andrey

On 2021-09-20 10:20 p.m., Felix Kuehling wrote:

Am 2021-09-20 um 5:55 p.m. schrieb Philip Yang:

Don't use devm_request_free_mem_region to alloc VRAM region for pgmap,

devm_... refers to a device manager that automatically releases
device-specific resources when a driver disconnects from a device. So
maybe that just means, our devm_memunmap_pages and
devm_release_mem_region calls in svm_migrate_fini are redundant, and the
best solution is to remove those calls.

See Documentation/driver-api/driver-model/devres.rst

Regards,
   Felix

because driver__detach releases all device resource region, then calls
amdgpu_device_fini_sw, which calls devm_memunmap_pages generating below
warning trace:

WARNING: CPU: 1 PID: 3646 at drivers/base/devres.c:795
devm_release_action+0x51/0x60
Call Trace:
     ? memunmap_pages+0x360/0x360
     svm_migrate_fini+0x2d/0x60 [amdgpu]
     kgd2kfd_device_exit+0x23/0xa0 [amdgpu]
     amdgpu_amdkfd_device_fini_sw+0x1d/0x30 [amdgpu]
     amdgpu_device_fini_sw+0x45/0x290 [amdgpu]
     amdgpu_driver_release_kms+0x12/0x30 [amdgpu]
     drm_dev_release+0x20/0x40 [drm]
     release_nodes+0x196/0x1e0
     device_release_driver_internal+0x104/0x1d0
     driver_detach+0x47/0x90
     bus_remove_driver+0x7a/0xd0
     pci_unregister_driver+0x3d/0x90
     amdgpu_exit+0x11/0x20 [amdgpu]
Trying to free nonexistent resource <000007fc00000000-000007fdffffffff>

Signed-off-by: Philip Yang <philip.y...@amd.com>
---
  drivers/gpu/drm/amd/amdkfd/kfd_migrate.c | 13 ++++++-------
  1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c 
b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
index 21f745e0b86c..aa96767920a9 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
@@ -880,7 +880,7 @@ int svm_migrate_init(struct amdgpu_device *adev)
         * should remove reserved size
         */
        size = ALIGN(adev->gmc.real_vram_size, 2ULL << 20);
-       res = devm_request_free_mem_region(adev->dev, &iomem_resource, size);
+       res = request_free_mem_region(&iomem_resource, size, "amdgpu_vram");
        if (IS_ERR(res))
                return -ENOMEM;

@@ -891,14 +891,13 @@ int svm_migrate_init(struct amdgpu_device *adev)

        pgmap->ops = &svm_migrate_pgmap_ops;
        pgmap->owner = SVM_ADEV_PGMAP_OWNER(adev);
        pgmap->flags = MIGRATE_VMA_SELECT_DEVICE_PRIVATE;
-       r = devm_memremap_pages(adev->dev, pgmap);
+       r = memremap_pages(pgmap, dev_to_node(adev->dev));
        if (IS_ERR(r)) {
                pr_err("failed to register HMM device memory\n");

/* Disable SVM support capability */

                pgmap->type = 0;
-               devm_release_mem_region(adev->dev, res->start,
-                                       res->end - res->start + 1);
+               release_mem_region(res->start, res->end - res->start + 1);
                return PTR_ERR(r);
        }

@@ -919,7 +918,7 @@ void svm_migrate_fini(struct amdgpu_device *adev)

        if (!KFD_IS_SVM_API_SUPPORTED(adev->kfd.dev))
                return;

- devm_memunmap_pages(adev->dev, pgmap);

-       devm_release_mem_region(adev->dev, pgmap->range.start,
-                               pgmap->range.end - pgmap->range.start + 1);
+       memunmap_pages(pgmap);
+       release_mem_region(pgmap->range.start,
+                          pgmap->range.end - pgmap->range.start + 1);
  }