Description
In the Linux kernel, the following vulnerability has been resolved:
ext4: fix out of bounds punch offset
Punching a hole with a start offset that exceeds max_end is not
permitted and will result in a negative length in the
truncate_inode_partial_folio() function while truncating the page cache,
potentially leading to undesirable consequences.
A simple reproducer:
truncate -s 9895604649994 /mnt/foo
xfs_io -c "pwrite 8796093022208 4096" /mnt/foo
xfs_io -c "fpunch 8796093022213 25769803777" /mnt/foo
kernel BUG at include/linux/highmem.h:275!
Oops: invalid opcode: 0000 [#1] SMP PTI
CPU: 3 UID: 0 PID: 710 Comm: xfs_io Not tainted 6.15.0-rc3
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-2.fc40 04/01/2014
RIP: 0010:zero_user_segments.constprop.0+0xd7/0x110
RSP: 0018:ffffc90001cf3b38 EFLAGS: 00010287
RAX: 0000000000000005 RBX: ffffea0001485e40 RCX: 0000000000001000
RDX: 000000000040b000 RSI: 0000000000000005 RDI: 000000000040b000
RBP: 000000000040affb R08: ffff888000000000 R09: ffffea0000000000
R10: 0000000000000003 R11: 00000000fffc7fc5 R12: 0000000000000005
R13: 000000000040affb R14: ffffea0001485e40 R15: ffff888031cd3000
FS: 00007f4f63d0b780(0000) GS:ffff8880d337d000(0000)
knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000001ae0b038 CR3: 00000000536aa000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
truncate_inode_partial_folio+0x3dd/0x620
truncate_inode_pages_range+0x226/0x720
? bdev_getblk+0x52/0x3e0
? ext4_get_group_desc+0x78/0x150
? crc32c_arch+0xfd/0x180
? __ext4_get_inode_loc+0x18c/0x840
? ext4_inode_csum+0x117/0x160
? jbd2_journal_dirty_metadata+0x61/0x390
? __ext4_handle_dirty_metadata+0xa0/0x2b0
? kmem_cache_free+0x90/0x5a0
? jbd2_journal_stop+0x1d5/0x550
? __ext4_journal_stop+0x49/0x100
truncate_pagecache_range+0x50/0x80
ext4_truncate_page_cache_block_range+0x57/0x3a0
ext4_punch_hole+0x1fe/0x670
ext4_fallocate+0x792/0x17d0
? __count_memcg_events+0x175/0x2a0
vfs_fallocate+0x121/0x560
ksys_fallocate+0x51/0xc0
__x64_sys_fallocate+0x24/0x40
x64_sys_call+0x18d2/0x4170
do_syscall_64+0xa7/0x220
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Fix this by filtering out cases where the punching start offset exceeds
max_end.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Linux | Linux | 6.15 | 6.15.4 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 24.04 LTS | linux-riscv +6 | No fix yet | — |
| Ubuntu 22.04 LTS | linux-riscv +32 | No fix yet | — |
| Ubuntu 20.04 LTS | linux-gke +28 | No fix yet | — |
| Ubuntu 18.04 LTS | linux-gcp +14 | No fix yet | — |
| Ubuntu 16.04 LTS | linux-hwe-edge | No fix yet | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 9 | kernel-uek +34 | 6.12.0-104.43.4.2.el10uek | ELSA-2025-20662 |
Advisories 2
- WID-SEC-2025-1465 Linux Kernel: Mehrere Schwachstellen ermöglichen Denial of Service BSI CERT-Bund (WID) · Nov 12, 2026
- ELSA-2025-20662 Important: Unbreakable Enterprise kernel security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Oct 14, 2025