CVE-2024-39477

En el kernel de Linux, se resolvió la siguiente vulnerabilidad: mm/hugetlb: no llame a vma_add_reservation cuando ENOMEM sysbot informó un splat [1] en __unmap_hugepage_range(). Esto se debe a que vma_needs_reservation() puede devolver -ENOMEM si allocate_file_region_entries() no puede asignar la estructura file_region para la reserva. Verifique eso y no llame a vma_add_reservation() si ese es el caso; de lo contrario, region_abort() y region_del() verán que no tenemos ningún file_regions. Si detectamos que vma_needs_reservation() devolvió -ENOMEM, borramos el indicador hugetlb_restore_reserve como si esta reserva todavía estuviera consumida, por lo que free_huge_folio() no incrementará el recuento de resv. [1] https://lore.kernel.org/linux-mm/0000000000004096100617c58d54@google.com/T/#ma5983bc1ab18a54910da83416b3f89f3c7ee43aa

In the Linux kernel, the following vulnerability has been resolved: mm/hugetlb: do not call vma_add_reservation upon ENOMEM sysbot reported a splat [1] on __unmap_hugepage_range(). This is because vma_needs_reservation() can return -ENOMEM if allocate_file_region_entries() fails to allocate the file_region struct for the reservation. Check for that and do not call vma_add_reservation() if that is the case, otherwise region_abort() and region_del() will see that we do not have any file_regions. If we detect that vma_needs_reservation() returned -ENOMEM, we clear the hugetlb_restore_reserve flag as if this reservation was still consumed, so free_huge_folio() will not increment the resv count. [1] https://lore.kernel.org/linux-mm/0000000000004096100617c58d54@google.com/T/#ma5983bc1ab18a54910da83416b3f89f3c7ee43aa