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Fencer Vulns
no cvss —

CVE-2026-97549 json

xfs: fix under-reservation of blocks when repairing sf directories

published 2026-09-25 44 d ago modified 2026-10-19 20 d ago also EUVD-2026-86857

cvss
—
not scored
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 10%
public exploits
0
none known

Summary

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

xfs: fix under-reservation of blocks when repairing sf directories

Whilst running QA on XFS for-next as of 7.3-rc2 with MKFS_OPTIONS="-n size=8192", I observed the following (trimmed) dmesg splat:

XFS: Assertion failed: args->total >= dp->i_nblocks - nblks, file: fs/xfs/libxfs/xfs_da_btree.c, line: 2387 WARNING: fs/xfs/xfs_message.c:104 at assfail+0x46/0x4a [xfs], CPU#0: xfs_scrub/1426511 CPU: 0 UID: 0 PID: 1426511 Comm: xfs_scrub Tainted: G W 7.3.0-rc2-djwx #rc2 PREEMPT(lazy) 6e418570b606a39783b0e7e7b30dc407b965f9e8 Tainted: [W]=WARN RIP: 0010:assfail+0x46/0x4a [xfs] RSP: 0018:ffffc900010d7890 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00000000ffffffd1 RDX: 0000000000000000 RSI: 0000000000000021 RDI: ffffffffa059fd38 RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000 R10: 000000000000000a R11: 000000007fffffff R12: ffffc900010d7940 R13: ffff888368d8f980 R14: ffffc900010d7a48 R15: ffffc900010d78d0 FS: 00007f445c5ce680(0000) GS:ffff8884a97ea000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f443803b9a8 CR3: 0000000107a4b000 CR4: 00000000003506f0 Call Trace: <TASK> xfs_da_grow_inode_int+0x2e0/0x300 [xfs 5de2257e14108c136f11317e6bbb8ac77efd392c] xfs_dir2_grow_inode+0x6e/0x150 [xfs 5de2257e14108c136f11317e6bbb8ac77efd392c] xfs_dir2_sf_to_block+0x149/0x870 [xfs 5de2257e14108c136f11317e6bbb8ac77efd392c] xrep_dir_swap_prep+0xe2/0x110 [xfs 5de2257e14108c136f11317e6bbb8ac77efd392c] xrep_dir_swap+0xfb/0x2f0 [xfs 5de2257e14108c136f11317e6bbb8ac77efd392c] xrep_dir_rebuild_tree+0x99/0x100 [xfs 5de2257e14108c136f11317e6bbb8ac77efd392c] xrep_directory+0x83/0x1c0 [xfs 5de2257e14108c136f11317e6bbb8ac77efd392c] xrep_attempt+0x4f/0x1e0 [xfs 5de2257e14108c136f11317e6bbb8ac77efd392c] xfs_scrub_metadata+0x393/0x5b0 [xfs 5de2257e14108c136f11317e6bbb8ac77efd392c] xfs_ioc_scrubv_metadata+0x306/0x570 [xfs 5de2257e14108c136f11317e6bbb8ac77efd392c] xfs_file_ioctl+0xa4f/0x1150 [xfs 5de2257e14108c136f11317e6bbb8ac77efd392c] __x64_sys_ioctl+0x76/0xc0 do_syscall_64+0x7a/0x3b0 entry_SYSCALL_64_after_hwframe+0x4b/0x53

This is a consequence of commit 0fe77e57588b98, which added the following assertion to xfs_da_grow_inode_int:

ASSERT(args->total >= dp->i_nblocks - nblks);

Tracing this back to xrep_dir_swap_prep, I noticed that the xfs_da_args object that's passed to xfs_dir2_sf_to_block sets args->total to 1. This is incorrect because mkfs set the directory block size to 8k and the filesystem block size to 4k. In other words, args->total should be 2 here, not 1.

Dave Chinner tripped over the same problem with the same branch through a different channel -- his test setup set the fs block size to 1k, in which case the directory block size is still set to 4k. Here, args->total should be 4.

Changing the assignment of args->total to sc->mp->m_dir_geo->fsbcount makes the assertion go away, but that isn't a complete fix. In xrep_tempexch_estimate, we also incorrectly assume that a shortform conversion requires 1 fsblock when it should be m_dir_geo->fsbcount. Without that, we can under-reserve space in the transaction and cause a filesystem shutdown.

Note that the xfs_dabuf_nfsb helper will compute the correct value for directories and xattr, so we use that instead of open-coding the logic. Also fix xrep_xattr_swap_prep to assign args->total via xfs_dabuf_nfsb to avoid one logic bomb if we ever support multi-fsblock attrs.

Tripped-by: 0fe77e57588b98 ("xfs: assert the reservation covers each da fork growth")

Patch / fix

  • Linux Linux 6.12.112, 6.18.54, 7.2.7, 7.3
  • linux Debian 13 6.12.113-1
  • linux Debian 14 7.2.7-1
  • linux-6.12 Debian 12 6.12.113-1~deb12u1

debian advisories DEBIAN-CVE-2026-97549

  • linux Ubuntu 26.04 LTS 7.0.0-42.42
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1016.17
  • linux-gcp Ubuntu 26.04 LTS 7.0.0-1016.18
  • linux-ibm Ubuntu 26.04 LTS 7.0.0-1017.17
  • linux-riscv Ubuntu 26.04 LTS 7.0.0-42.42.1
  • linux-oracle Ubuntu 26.04 LTS 7.0.0-1015.16
  • linux-hwe-7.0 Ubuntu 24.04 LTS 7.0.0-42.42~24.04.1
  • linux-oem-7.0 Ubuntu 26.04 LTS 7.0.0-1017.17

ubuntu advisories UBUNTU-CVE-2026-97549

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel-source openSUSE Tumbleweed 7.2.9-1.1

opensuse advisories openSUSE-SU-2026:12074-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-97549 updated cvss 5.5

kernel: xfs: fix under-reservation of blocks when repairing sf directories

  • Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +82 more Red Hat Enterprise Linux 10 kernel Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-9 Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 kernel-rt, kernel-rt-selftests-internal Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.21% chance of exploitation in the next 30 days, higher than 10% of all scored CVEs (FIRST EPSS, 2026-11-08).

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

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