Am 08.07.21 um 21:36 schrieb Alex Deucher:
From: Felix Kuehling <Felix.Kuehling@xxxxxxx>
KFD Thunk maps invisible VRAM BOs with PROT_NONE, MAP_PRIVATE.
is_cow_mapping returns true for these mappings. Add a check for
vm_flags & VM_WRITE to avoid mmap failures on private read-only or
PROT_NONE mappings.
I'm pretty sure that this is not working as expected.
Fixes: f91142c62161 ("drm/ttm: nuke VM_MIXEDMAP on BO mappings v3")
Signed-off-by: Felix Kuehling <Felix.Kuehling@xxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
---
drivers/gpu/drm/ttm/ttm_bo_vm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c
index f56be5bc0861..a75e90c7d4aa 100644
--- a/drivers/gpu/drm/ttm/ttm_bo_vm.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c
@@ -552,7 +552,7 @@ static const struct vm_operations_struct ttm_bo_vm_ops = {
int ttm_bo_mmap_obj(struct vm_area_struct *vma, struct ttm_buffer_object *bo)
{
/* Enforce no COW since would have really strange behavior with it. */
- if (is_cow_mapping(vma->vm_flags))
+ if (is_cow_mapping(vma->vm_flags) && (vma->vm_flags & VM_WRITE))
is_cow_mapping() already checks for VM_MAYWRITE, so this here shouldn't
be necessary.
Christian.
return -EINVAL;
ttm_bo_get(bo);
