In the Linux kernel, the following vulnerability has been resolved:
ring-buffer: Check resize_disabled before publishing the new subbuf order
ring_buffer_subbuf_order_set() stores the new order and only then walks
the CPUs, returning -EBUSY if any of them has resizing disabled. A user
mapped buffer has resizing disabled, and __rb_map_vma() reads
buffer->subbuf_order without buffer->mutex, so an mmap of an already
mapped CPU racing the failing order change sizes the mapping with the
new order and inserts pages past the sub-buffer into the VMA.
Check the CPUs before storing the new order.
References 4
https://git.kernel.org/stable/c/32bf47db9237c5b8b6f6aaa5356bb4c79d241f76
416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/9fd4ea952e6ac12a63c3fe89f08ad02771aa2c06
416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/d860c67c051685abb0460b593b193f0f45f4fa92
416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/f2099644e1b2a2c0805c5240d63ab0522d9d0174
416baaa9-dc9f-4396-8d5f-8c081fb06d67