In the Linux kernel, the following vulnerability has been resolved:
net/mlx5e: Use a memory barrier to enforce PTP WQ xmit submission tracking occurs after populating the metadata_map
Just simply reordering the functions mlx5eptpmetadatamapput and mlx5eptpsqtrackmetadata in the mlx5etxwqecomplete context is not good enough since both the compiler and CPU are free to reorder these two functions. If reordering does occur, the issue that was supposedly fixed by 7e3f3ba97e6c ("net/mlx5e: Track xmit submission to PTP WQ after populating metadata map") will be seen. This will lead to NULL pointer dereferences in mlx5eptpsqmarktscqesundelivered in the NAPI polling context due to the tracking list being populated before the metadata map.