Am 10.09.2018 um 09:19 schrieb Deng, Emily:
-----Original Message-----
From: Christian König <ckoenig.leichtzumer...@gmail.com>
Sent: Monday, September 10, 2018 3:06 PM
To: Deng, Emily <emily.d...@amd.com>; amd-gfx@lists.freedesktop.org
Subject: Re: [PATCH] drm/amdgpu: Fix the dead lock issue.
Am 10.09.2018 um 06:07 schrieb Emily Deng:
It will ramdomly have the dead lock issue when test TDR:
1. amdgpu_device_handle_vram_lost gets the lock shadow_list_lock 2.
amdgpu_bo_create locked the bo's resv lock 3. amdgpu_bo_create_shadow
is waiting for the shadow_list_lock 4.
amdgpu_device_recover_vram_from_shadow is waiting for the bo's resv
lock.
Signed-off-by: Emily Deng <emily.d...@amd.com>
Good catch, problem is the fix doesn't work like this because the lock won't be
dropped at this point in most cases.
Sorry, could you explain more, why the lock won't be dropped after calling
reservation_object_unlock?
reservation_object_unlock won't be called for most BOs.
E.g. the shadow is used for page directories and all page directories
use the root reservation object and so have bp->resv set here.
Christian.
Instead you need to fix amdgpu_device_recover_vram_from_shadow to make
a local copy of the list.
You can do this by grabbing a reference to each BO and moving it to a local
list.
Regards,
Christian.
---
drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
index de990bd..c75447d 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
@@ -557,12 +557,8 @@ static int amdgpu_bo_create_shadow(struct
amdgpu_device *adev,
bp.resv = bo->tbo.resv;
r = amdgpu_bo_do_create(adev, &bp, &bo->shadow);
- if (!r) {
+ if (!r)
bo->shadow->parent = amdgpu_bo_ref(bo);
- mutex_lock(&adev->shadow_list_lock);
- list_add_tail(&bo->shadow_list, &adev->shadow_list);
- mutex_unlock(&adev->shadow_list_lock);
- }
return r;
}
@@ -603,6 +599,12 @@ int amdgpu_bo_create(struct amdgpu_device
*adev,
if (!bp->resv)
reservation_object_unlock((*bo_ptr)->tbo.resv);
+ if (!r) {
+ mutex_lock(&adev->shadow_list_lock);
+ list_add_tail(&(*bo_ptr)->shadow_list, &adev-
shadow_list);
+ mutex_unlock(&adev->shadow_list_lock);
+ }
+
if (r)
amdgpu_bo_unref(bo_ptr);
}
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