Am 16.10.23 um 14:15 schrieb Karolina Stolarek:
With the current cleanup flow, we could trigger a NULL pointer
dereference if there is a delayed destruction of a BO with a
system resource that gets executed on drain_workqueue() call,
as we attempt to free a resource using an already released
resource manager.
Remove the device from the device list and drain its workqueue
before releasing the system domain manager in ttm_device_fini().
Signed-off-by: Karolina Stolarek <karolina.stolarek@xxxxxxxxx>
Reviewed and pushed to drm-misc-fixes.
Thanks,
Christian
---
This is actually a reiteration of a patch sent in [1], but the
solution and commit message changed significantly, so I decided
not to send it as v2.
[1] - 20231013143423.1503088-1-karolina.stolarek@xxxxxxxxx
drivers/gpu/drm/ttm/ttm_device.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/ttm/ttm_device.c b/drivers/gpu/drm/ttm/ttm_device.c
index 7726a72befc5..d48b39132b32 100644
--- a/drivers/gpu/drm/ttm/ttm_device.c
+++ b/drivers/gpu/drm/ttm/ttm_device.c
@@ -232,10 +232,6 @@ void ttm_device_fini(struct ttm_device *bdev)
struct ttm_resource_manager *man;
unsigned i;
- man = ttm_manager_type(bdev, TTM_PL_SYSTEM);
- ttm_resource_manager_set_used(man, false);
- ttm_set_driver_manager(bdev, TTM_PL_SYSTEM, NULL);
-
mutex_lock(&ttm_global_mutex);
list_del(&bdev->device_list);
mutex_unlock(&ttm_global_mutex);
@@ -243,6 +239,10 @@ void ttm_device_fini(struct ttm_device *bdev)
drain_workqueue(bdev->wq);
destroy_workqueue(bdev->wq);
+ man = ttm_manager_type(bdev, TTM_PL_SYSTEM);
+ ttm_resource_manager_set_used(man, false);
+ ttm_set_driver_manager(bdev, TTM_PL_SYSTEM, NULL);
+
spin_lock(&bdev->lru_lock);
for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i)
if (list_empty(&man->lru[0]))
