CVE-2026-31648

Debolezza

In the Linux kernel, the following vulnerability has been resolved: mm: filemap: fix nr_pages calculation overflow in filemap_map_pages() When running stress-ng on my Arm64 machine with v7.0-rc3 kernel, I encountered some very strange crash issues showing up as "Bad page state": " [ 734.496287] BUG: Bad page state in process stress-ng-env pfn:415735fb [ 734.496427] page: refcount:0 mapcount:1 mapping:0000000000000000 index:0x4cf316 pfn:0x415735fb [ 734.496434] flags: 0x57fffe000000800(owner_2|node=1|zone=2|lastcpupid=0x3ffff) [ 734.496439] raw: 057fffe000000800 0000000000000000 dead000000000122 0000000000000000 [ 734.496440] raw: 00000000004cf316 0000000000000000 0000000000000000 0000000000000000 [ 734.496442] page dumped because: nonzero mapcount " After analyzing this page’s state, it is hard to understand why the mapcount is not 0 while the refcount is 0, since this page is not where the issue first occurred. By enabling the CONFIG_DEBUG_VM config, I can reproduce the crash as well and captured the first warning where the issue appears: " [ 734.469226] page: refcount:33 mapcount:0 mapping:00000000bef2d187 index:0x81a0 pfn:0x415735c0 [ 734.469304] head: order:5 mapcount:0 entire_

Prodotti interessati

• linux linux_kernel

Riferimenti

• https://git.kernel.org/stable/c/576543bedd616254032d4ebe54a90076f9e31740
• https://git.kernel.org/stable/c/633ab680c405ac390e6bec5b74aaf46197c837b6
• https://git.kernel.org/stable/c/88591194df736a508dd5461ab2167a61e98caac1
• https://git.kernel.org/stable/c/9316a820b9aae07d44469d6485376dad824c5b3f
• https://git.kernel.org/stable/c/f58df566524ebcdfa394329c64f47e3c9257516e