drm/radeon: use mmu_notifier_get/put for struct radeon_mn

radeon is using a device global hash table to track what mmu_notifiers
have been registered on struct mm. This is better served with the new
get/put scheme instead.

radeon has a bug where it was not blocking notifier release() until all
the BO's had been invalidated. This could result in a use after free of
pages the BOs. This is tied into a second bug where radeon left the
notifiers running endlessly even once the interval tree became
empty. This could result in a use after free with module unload.

Both are fixed by changing the lifetime model, the BOs exist in the
interval tree with their natural lifetimes independent of the mm_struct
lifetime using the get/put scheme. The release runs synchronously and just
does invalidate_start across the entire interval tree to create the
required DMA fence.

Additions to the interval tree after release are already impossible as
only current->mm is used during the add.

Link: https://lore.kernel.org/r/20190806231548.25242-9-jgg@ziepe.ca
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
This commit is contained in:
Jason Gunthorpe
2019-08-06 20:15:45 -03:00
parent c7d8b7824f
commit 534e5f84b7
4 changed files with 44 additions and 132 deletions

View File

@@ -1325,8 +1325,6 @@ int radeon_device_init(struct radeon_device *rdev,
init_rwsem(&rdev->pm.mclk_lock);
init_rwsem(&rdev->exclusive_lock);
init_waitqueue_head(&rdev->irq.vblank_queue);
mutex_init(&rdev->mn_lock);
hash_init(rdev->mn_hash);
r = radeon_gem_init(rdev);
if (r)
return r;