CVE-2025-21931

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> hwpoison, memory_hotplug: lock folio before unmap hwpoisoned folio<br /> <br /> Commit b15c87263a69 ("hwpoison, memory_hotplug: allow hwpoisoned pages to<br /> be offlined) add page poison checks in do_migrate_range in order to make<br /> offline hwpoisoned page possible by introducing isolate_lru_page and<br /> try_to_unmap for hwpoisoned page. However folio lock must be held before<br /> calling try_to_unmap. Add it to fix this problem.<br /> <br /> Warning will be produced if folio is not locked during unmap:<br /> <br /> ------------[ cut here ]------------<br /> kernel BUG at ./include/linux/swapops.h:400!<br /> Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP<br /> Modules linked in:<br /> CPU: 4 UID: 0 PID: 411 Comm: bash Tainted: G W 6.13.0-rc1-00016-g3c434c7ee82a-dirty #41<br /> Tainted: [W]=WARN<br /> Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015<br /> pstate: 40400005 (nZcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)<br /> pc : try_to_unmap_one+0xb08/0xd3c<br /> lr : try_to_unmap_one+0x3dc/0xd3c<br /> Call trace:<br /> try_to_unmap_one+0xb08/0xd3c (P)<br /> try_to_unmap_one+0x3dc/0xd3c (L)<br /> rmap_walk_anon+0xdc/0x1f8<br /> rmap_walk+0x3c/0x58<br /> try_to_unmap+0x88/0x90<br /> unmap_poisoned_folio+0x30/0xa8<br /> do_migrate_range+0x4a0/0x568<br /> offline_pages+0x5a4/0x670<br /> memory_block_action+0x17c/0x374<br /> memory_subsys_offline+0x3c/0x78<br /> device_offline+0xa4/0xd0<br /> state_store+0x8c/0xf0<br /> dev_attr_store+0x18/0x2c<br /> sysfs_kf_write+0x44/0x54<br /> kernfs_fop_write_iter+0x118/0x1a8<br /> vfs_write+0x3a8/0x4bc<br /> ksys_write+0x6c/0xf8<br /> __arm64_sys_write+0x1c/0x28<br /> invoke_syscall+0x44/0x100<br /> el0_svc_common.constprop.0+0x40/0xe0<br /> do_el0_svc+0x1c/0x28<br /> el0_svc+0x30/0xd0<br /> el0t_64_sync_handler+0xc8/0xcc<br /> el0t_64_sync+0x198/0x19c<br /> Code: f9407be0 b5fff320 d4210000 17ffff97 (d4210000)<br /> ---[ end trace 0000000000000000 ]---