In the Linux kernel, the following vulnerability has been resolved: ARM: 9359/1: flush: check if the folio is reserved for no-mapping addresses Since commit a4d5613c4dc6 ("arm: extend pfn_valid to take into account freed memory map alignment") changes the semantics of pfn_valid() to check presence of the memory map for a PFN. A valid page for an address which is reserved but not mapped by the kernel[1], the system crashed during some uio test with the following memory layout: node 0: [mem 0x00000000c0a00000-0x00000000cc8fffff] node 0: [mem 0x00000000d0000000-0x00000000da1fffff] the uio layout is：0xc0900000, 0x100000 the crash backtrace like: Unable to handle kernel paging request at virtual address bff00000 [...] CPU: 1 PID: 465 Comm: startapp.bin Tainted: G O 5.10.0 #1 Hardware name: Generic DT based system PC is at b15_flush_kern_dcache_area+0x24/0x3c LR is at __sync_icache_dcache+0x6c/0x98 [...] (b15_flush_kern_dcache_area) from (__sync_i…