On 6/10/25 18:42, Tvrtko Ursulin wrote:
Protect the access to driver and timeline name which otherwise could be freed as dma-fence exported is signalling fences.
This prepares the code for incoming dma-fence API changes which will start asserting these accesses are done from a RCU locked section.
Signed-off-by: Tvrtko Ursulin tvrtko.ursulin@igalia.com
Reviewed-by: Christian König christian.koenig@amd.com
drivers/dma-buf/sync_file.c | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-)
diff --git a/drivers/dma-buf/sync_file.c b/drivers/dma-buf/sync_file.c index 212df4b849fe..747e377fb954 100644 --- a/drivers/dma-buf/sync_file.c +++ b/drivers/dma-buf/sync_file.c @@ -135,12 +135,18 @@ char *sync_file_get_name(struct sync_file *sync_file, char *buf, int len) strscpy(buf, sync_file->user_name, len); } else { struct dma_fence *fence = sync_file->fence;
const char __rcu *timeline;const char __rcu *driver;
rcu_read_lock();driver = dma_fence_driver_name(fence);timeline = dma_fence_timeline_name(fence);
dma_fence_driver_name(fence),dma_fence_timeline_name(fence),
rcu_dereference(driver),rcu_dereference(timeline), fence->context, fence->seqno);rcu_read_unlock();return buf; @@ -262,9 +268,17 @@ static long sync_file_ioctl_merge(struct sync_file *sync_file, static int sync_fill_fence_info(struct dma_fence *fence, struct sync_fence_info *info) {
- strscpy(info->obj_name, dma_fence_timeline_name(fence),
- const char __rcu *timeline;
- const char __rcu *driver;
- rcu_read_lock();
- driver = dma_fence_driver_name(fence);
- timeline = dma_fence_timeline_name(fence);
- strscpy(info->obj_name, rcu_dereference(timeline), sizeof(info->obj_name));
- strscpy(info->driver_name, dma_fence_driver_name(fence),
- strscpy(info->driver_name, rcu_dereference(driver), sizeof(info->driver_name));
info->status = dma_fence_get_status(fence); @@ -273,6 +287,8 @@ static int sync_fill_fence_info(struct dma_fence *fence, ktime_to_ns(dma_fence_timestamp(fence)) : ktime_set(0, 0);
- rcu_read_unlock();
- return info->status;
}