In the Linux kernel, the following vulnerability has been resolved:
accel/amxdna: Fix page-insertion errors in amdxdna_insert_pages()
Two error paths in amdxdna_insert_pages() called vma->vm_ops->close(vma)
before returning an error code to the caller. This is incorrect:
amdxdna_gem_obj_mmap() registers an HMM interval notifier before calling
amdxdna_insert_pages(), and on a hard error it jumps to hmm_unreg to undo
that registration. Calling vm_ops->close() manually — which drops the
shmem pages_pin_count and the GEM object reference that backs the VMA —
before the mmap syscall has even returned causes those resources to be
released while the VMA is still alive. The kernel VMA teardown will call
vm_ops->close() a second time when the process later unmaps the range,
producing a reference count underflow.
Replace both hard-error returns with a deferred-fault approach that keeps
the VMA alive and retries page insertion through the HMM range-fault path.
