Linux Kernel Cacheinfo Signed Error Value Misassignment Vulnerability

A vulnerability in the Linux kernel's cacheinfo handling for arm64 architecture has been addressed. The issue arose from an incorrect assignment of a signed error value to an unsigned variable, fw_level. The function acpi_find_last_cache_level() began returning -ENOENT when no PPTT table was found, but this negative value was improperly assigned to fw_level, leading to an incorrect calculation of cache leaves. This miscalculation could cause __alloc_pages to issue a warning, as the order would exceed MAX_ORDER due to the inflated cache leaves value.

Impact

Exploitation of this vulnerability could lead to a denial-of-service condition, where the system becomes unresponsive or fails to allocate memory properly, potentially causing critical processes to hang or fail.