CVE-2025-40006 — mm/hugetlb: fix folio is still mapped when deleted

Affected: Linux

In the Linux kernel, the following vulnerability has been resolved:

mm/hugetlb: fix folio is still mapped when deleted

Migration may be raced with fallocating hole. remove_inode_single_folio will unmap the folio if the folio is still mapped. However, it's called without folio lock. If the folio is migrated and the mapped pte has been converted to migration entry, folio_mapped() returns false, and won't unmap it. Due to extra refcount held by remove_inode_single_folio, migration fails, restores migration entry to normal pte, and the folio is mapped again. As a result, we triggered BUG in filemap_unaccount_folio.

The log is as follows: BUG: Bad page cache in process hugetlb pfn:156c00 page: refcount:515 mapcount:0 mapping:0000000099fef6e1 index:0x0 pfn:0x156c00 head: order:9 mapcount:1 entire_mapcount:1 nr_pages_mapped:0 pincount:0 aops:hugetlbfs_aops ino:dcc dentry name(?):"my_hugepage_file" flags: 0x17ffffc00000c1(locked|waiters|head|node=0|zone=2|lastcpupid=0x1fffff) page_type: f4(hugetlb) page dumped because: still mapped when deleted CPU: 1 UID: 0 PID: 395 Comm: hugetlb Not tainted 6.17.0-rc5-00044-g7aac71907bde-dirty #484 NONE Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015 Call Trace: <TASK> dump_stack_lvl+0x4f/0x70 filemap_unaccount_folio+0xc4/0x1c0 __filemap_remove_folio+0x38/0x1c0 filemap_remove_folio+0x41/0xd0 remove_inode_hugepages+0x142/0x250 hugetlbfs_fallocate+0x471/0x5a0 vfs_fallocate+0x149/0x3…

USN-8033-1 — linux, linux-aws, linux-gcp, linux-gke, linux-gkeop, linux-hwe-5.15, linux-ibm, linux-ibm-5.15, linux-lowlatency, linux…

Affected: Ubuntu:Pro:20.04:LTS: linux-hwe-5.15, Ubuntu:Pro:20.04:LTS: linux-ibm-5.15, Ubuntu:Pro:20.04:LTS: linux-lowlatency-hwe-5.15, Ubuntu:22.04:LTS: linux, Ubuntu:22.04:LTS: linux-aws, Ubuntu:22.04:LTS: linux-gcp, Ubuntu:22.04:LTS: linux-gke, Ubuntu:22.04:LTS: linux-gkeop, Ubuntu:22.04:LTS: linux-ibm, Ubuntu:22.04:LTS: linux-lowlatency

Several security issues were discovered in the Linux kernel. An attacker could possibly use these to compromise the system. This update corrects flaws in the following subsystems: - Nios II architecture; - Sun Sparc architecture; - User-Mode Linux (UML); - x86 architecture; - Block layer subsystem; - Cryptographic API; - Drivers core; - Bus devices; - Hardware random number generator core; - Data acquisition framework and drivers; - CPU frequency scaling framework; - DMA engine subsystem; - GPU drivers; - HW tracing; - Input Device (Miscellaneous) drivers; - Multiple devices driver; - Media drivers; - MOST (Media Oriented Systems Transport) drivers; - MTD block device drivers; - Network drivers; - NVME drivers; - PCI subsystem; - Performance monitor drivers; - Pin controllers subsystem; - x86 platform drivers; - PPS (Pulse Per Second) driver; - PWM drivers; - SCSI subsystem; - TCM subsystem; - Userspace I/O drivers; - USB Gadget drivers; - USB Host Controller drivers; - Framebuffer layer; - BTRFS file system; - File systems infrastructure; - Ext4 file system; - Network file system (NFS) server daemon; - NTFS3 file system; - SMB network file system; - padata parallel execution mechanism; - IP tunnels definitions; - Network sockets; - XFRM subsystem; - Control group (cgroup); - Padata parallel execution mechanism; - PID allocator; - Tracing infrastructure; - Memory management; - 9…

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CVE-2025-40006 — mm/hugetlb: fix folio is still mapped when deleted

USN-8033-1 — linux, linux-aws, linux-gcp, linux-gke, linux-gkeop, linux-hwe-5.15, linux-ibm, linux-ibm-5.15, linux-lowlatency, linux…