On Mon, 11 May 2026 06:18:44 -0700 Rob Clark <[email protected]> wrote:
> On Fri, May 8, 2026 at 3:41 AM Boris Brezillon > <[email protected]> wrote: > > > > Recently, a few races have been discovered in the GEM LRU logic, all > > of them caused by the fact the LRU lock is accessed through > > gem->lru->lock, and that lock itself also protects changes to > > gem->lru, leading to situations where gem->lru needs to first be > > accessed without the lock held, to then get the lru to access the lock > > through and finally take the lock and do the expected operation. > > > > Currently, the two drivers making use of this API declare device-wide > > locks, and there's no clue that we will ever have a driver that wants > > different pools of LRUs protected by different locks under the same > > drm_device. So we're better off moving this lock to drm_device and > > always locking it through obj->dev->gem_lru_mutex, or directly through > > dev->gem_lru_mutex. > > > > If anyone ever needs more fine-grained locking, this can be revisited > > to pass some drm_gem_lru_pool object represent the pool of LRUs under > > a specific lock, but for now, the per-device lock seems to be enough. > > > > Signed-off-by: Boris Brezillon <[email protected]> > > Reviewed-by: Rob Clark <[email protected]> If every one is happy with patch 4, I'm tempted to drop patch 1 and 3, since they are irrelevant if the locking is fixed the way it is in this patch. Question is, do we care about patch 2 being backported to stable kernels then?
