Allowing userptr bo which are basicly a list of page from some vma
(so either anonymous page or file backed page) would lead to serious
corruption of kernel structures and counters (because we overwrite
the page->mapping field when mapping buffer).
This will already block if the buffer was populated before anyone does
try to mmap it because then TTM_PAGE_FLAG_SG would be set in in the
ttm_tt flags. But that flag is check before ttm_tt_populate in the ttm
vm fault handler.
So to be safe just add a check to verify_access() callback.
Signed-off-by: Jérôme Glisse <jglisse at redhat.com>
Cc: <stable at vger.kernel.org>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 6f3369d..11af449 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -223,6 +223,8 @@ static int amdgpu_verify_access(struct ttm_buffer_object
*bo, struct file *filp)
{
struct amdgpu_bo *rbo = container_of(bo, struct amdgpu_bo, tbo);
+ if (amdgpu_ttm_tt_get_usermm(bo->ttm))
+ return -EPERM;
return drm_vma_node_verify_access(&rbo->gem_base.vma_node, filp);
}
--
2.1.0
